Chin-Shang Li

University of California, Davis, Davis, California, United States

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Publications (86)214.38 Total impact

  • Shu-Hui Hsieh · Shen-Ming Lee · Chin-Shang Li · Su-Hao Tu
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    ABSTRACT: The randomized response technique (RRT) is an important tool that is commonly used to protect a respondent’s privacy and avoid biased answers in surveys on sensitive issues. In this work, we consider the joint use of the unrelated-question RRT of Greenberg et al. (J Am Stat Assoc 64:520–539, 1969) and the related-question RRT of Warner (J Am Stat Assoc 60:63–69, 1965) dealing with the issue of an innocuous question from the unrelated-question RRT. Unlike the existing unrelated-question RRT of Greenberg et al. (1969), the approach can provide more information on the innocuous question by using the related-question RRT of Warner (1965) to effectively improve the efficiency of the maximum likelihood estimator of Scheers and Dayton (J Am Stat Assoc 83:969–974, 1988). We can then estimate the prevalence of the sensitive characteristic by using logistic regression. In this new design, we propose the transformation method and provide large-sample properties. From the case of two survey studies, an extramarital relationship study and a cable TV study, we develop the joint conditional likelihood method. As part of this research, we conduct a simulation study of the relative efficiencies of the proposed methods. Furthermore, we use the two survey studies to compare the analysis results under different scenarios.
    No preview · Article · Jan 2016 · Statistical Methods and Applications
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    ABSTRACT: Objective: The pathophysiology of sudden unexpected death in epilepsy (SUDEP) remains undetermined. Seizures are accompanied by respiratory dysfunction (RD). Postictal generalized electroencephalography (EEG) suppression (PGES) may follow generalized tonic-clonic seizures (GTCS). Following GTCS patients have impaired arousal and may be motionless. Patients with SUDEP are usually prone. Postictal immobility (PI) may contribute to SUDEP by not permitting repositioning of the head to allow unimpeded ventilation. To determine whether RD and/or ictal characteristics are associated with PI, we analyzed patients with GTCS in the epilepsy monitoring unit. Method: We investigated for associations between PI duration and PGES, ictal/postictal oxygen saturation (SpO2 ), end-tidal CO2 (ETCO2 ), seizure localization, duration, and tonic and total convulsive phase duration. We investigated for linkage between PGES and these measures. Results: Seventy patients with 181 GTCS and available SpO2 and/or ETCO2 data were studied. Simple linear regression analysis by seizures showed that PI duration was associated with peak periictal ETCO2 (p = 0.03), duration of oxygen desaturation (p = 0.005) and with SpO2 nadir (p = 0.02). PI duration was not associated with tonic, convulsive phase or total seizure duration. Analysis by patients also showed significant association of PI with RD. Duration of PI was longer following seizures with PGES (p < 0.001). PGES was not associated with the tonic, convulsive phase or total seizure duration. SpO2 nadir was lower in seizures with PGES (p = 0.046), ETCO2 peak change (p = 0.003) was higher, and duration of ETCO2 elevation (p = 0.03) was longer. Multivariable regression analysis showed that PGES and severe RD were associated with PI duration. Significance: The duration of PI and presence of PGES are associated with periictal RD. The duration of PI is also associated with the presence of PGES. Seizure duration or duration of the convulsive phase is not associated with PI or PGES. Interventions aimed at reversing impaired arousal and PI may reduce SUDEP risk.
    No preview · Article · Jan 2016 · Epilepsia
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    ABSTRACT: Diabetes mellitus (DM) is a significant international health concern affecting more than 387 million individuals. A diabetic person has a 25% lifetime risk of developing a diabetic foot ulcer (DFU), leading to limb amputation in up to one in six DFU patients. Low-level light therapy (LLLT) uses low-power lasers or light-emitting diodes to alter cellular function and molecular pathways, and may be a promising treatment for DFU. The goal of this systematic review is to examine whether the clinical use of LLLT is effective in the healing of DFU at 12 weeks and 20 weeks in comparison with the standard of care, and to provide evidence-based recommendation and future clinical guidelines for the treatment of DFU using LLLT. On September 30th 2015, we searched PubMed, EMBASE, CINAHL, and Web of Science databases using the following terms: “diabetic foot” AND “low level light therapy,” OR “light emitting diode,” OR “phototherapy,” OR “laser.” The relevant articles that met the following criteria were selected for inclusion: randomized control trials (RCTs) that investigated the use of LLLT for treatment of DFU. Four RCTs involving 131 participants were suitable for inclusion based upon our criteria. The clinical trials used sham irriadiation, low dose, or non-therapeutic LLLT as placebo or control in comparison to LLLT. The endpoints included ulcer size and time to complete healing with follow-up ranging from 2 weeks to 16 weeks. Each article was assigned a level of evidence (LOE) and graded according to the Oxford Center for Evidence-based Medicine Levels of Evidence Grades of Recommendation criteria. Limitations of reviewed RCTs include a small sample size (N<100), unclear allocation concealment, lack of screening phase to exclude rapid healers, unclear inclusion/exclusion criteria, short (<30 days) follow-up period, and unclear treatment settings (wavelength and treatment time). However, all reviewed RCTs demonstrated therapeutic outcomes with no adverse events using LLLT for treatment of DFU. This systematic review reports that LLLT has significant potential to become a portable, minimally invasive, easy-to-use, and cost effective modality for treatment of DFU. To enthusiastically recommend LLLT for treatment of DFU, additional studies with comparable laser parameters, screening period to exclude rapid healers, larger sample sizes and longer follow-up periods are required. We envision future stringent RCTs may validate LLLT for treatment of DFU. Systematic review registration number: PROSPERO CRD42015029825. This article is protected by copyright. All rights reserved.
    No preview · Article · Jan 2016 · Wound Repair and Regeneration
  • T. Martin Lukusa · Shen-Ming Lee · Chin-Shang Li
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    ABSTRACT: Zero-inflated Poisson (ZIP) regression models have been widely used to study the effects of covariates in count data sets that have many zeros. However, often some covariates involved in ZIP regression modeling have missing values. Assuming that the selection probability is known or unknown and estimated via a non-parametric method, we propose the inverse probability weighting (IPW) method to estimate the parameters of the ZIP regression model with covariates missing at random. The asymptotic properties of the proposed estimators are studied in detail under certain regularity conditions. Both theoretical analysis and simulation results show that the semiparametric IPW estimator is more efficient than the true weight IPW estimator. The practical use of the proposed methodology is illustrated with data from a motorcycle survey of traffic regulations conducted in 2007 in Taiwan by the Ministry of Transportation and Communication.
    No preview · Article · Oct 2015 · Metrika
  • Minggen Lu · Chin-Shang Li
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    ABSTRACT: When the number of zeros in a count dataset exceeds the accommodation of the probability mass of a regular Poisson distribution at zero, the zero-inflated Poisson (ZIP) distribution is often used. To characterize the potential non-linear effects of covariates and avoid the “curse of dimensionality”, we propose a spline-based ZIP regression single-index model. B-splines are employed to estimate the unknown smooth function. A modified Fisher scoring method is proposed to simultaneously estimate the linear coefficients and the regression function. It is shown that the spline estimator of the nonparametric component is uniformly consistent, and achieves the optimal convergence rate under the smooth condition, and that the estimators of regression parameters are asymptotically normal and efficient. The spline-based semiparametric likelihood ratio test is also established. Moreover, a direct and consistent variance estimation method based on least-squares estimation is proposed. Simulations are performed to evaluate the proposed method.
    No preview · Article · Jul 2015 · Annals of the Institute of Statistical Mathematics
  • David J Boudreault · Chin-Shang Li · Michael S Wong
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    ABSTRACT: To evaluate the effect of web-based education on (1) patient satisfaction, (2) consultation times, and (3) conversion to surgery. A retrospective review of 767 new patient consultations seen by 4 university-based plastic surgeons was conducted between May 2012 and August 2013 to determine the effect a web-based education program has on patient satisfaction and consultation time. A standard 5-point Likert scale survey completed at the end of the consultation was used to assess satisfaction with their experience. Consult times were obtained from the electronic medical record. All analyses were done with Statistical Analysis Software version 9.2 (SAS Inc., Cary, NC). A P value less than 0.05 was considered statistically significant. Those who viewed the program before their consultation were more satisfied with their consultation compared to those who did not (satisfaction scores, mean ± SD: 1.13 ± 0.44 vs 1.36 ± 0.74; P = 0.02) and more likely to rate their experience as excellent (92% vs 75%; P = 0.02). Contrary to the claims of Emmi Solutions, patients who viewed the educational program before consultation trended toward longer visits compared to those who did not (mean time ± SD: 54 ± 26 vs 50 ± 35 minutes; P = 0.10). More patients who completed the program went on to undergo a procedure (44% vs 37%; P = 0.16), but this difference was not statistically significant. Viewing web-based educational programs significantly improved plastic surgery patients' satisfaction with their consultation, but patients who viewed the program also trended toward longer consultation times. Although there was an increase in converting to surgical procedures, this did not reach statistical significance.
    No preview · Article · Jun 2015 · Annals of plastic surgery
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    ABSTRACT: Radiation therapy (RT) is a standard component in the multimodality management of localized soft tissue sarcoma (STS). Increasing studies are focusing on biological modifiers that may influence the host's response to RT, including immunologic mechanisms known to change with the aging process. We hypothesized that the effects of RT would be influenced by age, contributing to differences in treatment outcome. Using Surveillance, Epidemiology, and End Results (1990-2011), we identified 30,898 adult patients (>18 y) with nonmetastatic STS undergoing initial surgery. We compared patient demographics, tumor characteristics, and treatments by age. Multivariable analyses were used to analyze overall survival (OS) and disease-specific survival (DSS). Hazard ratios (HRs) were calculated based on multivariable Cox proportional hazards models. Mean age at diagnosis was 56.6 ± 16.8 y, and 33.6% of patients were ≥65 y. Of the total, 52.1% of patients were male and 67% were white; 59.9% of patients underwent surgery alone, 33.3% received adjuvant RT, and 6.8% neoadjuvant RT. On multivariable analysis, age, sex, year of diagnosis, histology, grade, size, marital status, and RT predicted OS, whereas age, year of diagnosis, ethnicity, histology, site, grade, RT, size, and marital status predicted DSS. In all patients, RT was associated with improved OS and DSS compared to surgery alone (median OS 136 ± 13 mo with RT versus 118 ± 9 mo without RT and 5-y OS 63.2 ± 1.4% with RT versus 60.5 ± 1.2% without, P < 0.01). Patients ≥65 y derived greater improvements in OS and DSS compared with patients <65 y. These benefits were most notable after neoadjuvant RT with patients ≥65 y having significantly better OS (HR = 0.63; 95% confidence interval = 0.53-0.75), whereas patients <65 y did not (HR = 0.96; 95% confidence interval = 0.83-1.10). In addition, interaction testing demonstrated a significant modifier effect between RT and age (P < 0.05). RT is associated with improved survival in patients with STS undergoing surgical treatment, but improvements in oncologic outcome with RT were greatest among older patients. Further studies into the mechanism of these age-related effects are needed. Copyright © 2015 Elsevier Inc. All rights reserved.
    No preview · Article · Jun 2015 · Journal of Surgical Research

  • No preview · Article · Jun 2015 · Journal of Vascular Surgery
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    ABSTRACT: This study characterized physical activity and its association with injury among Latino farm workers. An interviewer-administered questionnaire was used to collect baseline and follow-up data on 843 and 640 Latino farm workers, respectively. Participants were 18-55 years old, engaged in farm work and residing in Mendota, CA at baseline interview. The questionnaire assessed self-reported physical activity and risk of injury. The 12 month prevalence of injury decreased from 9.0% at baseline to 6.9% at follow up interview. In GEE models adjusted for age, follow-up time, gender, smoking, income and years working in agriculture, poor/fair self-assessed health status (OR = 1.82, 95% CI: 1.18-2.82) and 2-3 hr per day of sitting/watching TV/using a computer (OR = 0.50, 95% CI: 0.30-0.83) were significantly associated with injury. Physical activity was not associated with injury in this population. Efforts to reduce injuries should focus on known risk factors such as poor health status. © 2015 Wiley Periodicals, Inc.
    Full-text · Article · May 2015 · American Journal of Industrial Medicine

  • No preview · Article · May 2015 · Plastic and Reconstructive Surgery
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    ABSTRACT: Racial/ethnic disparities in treatment outcomes of peripheral arterial disease (PAD) are well documented. Compared to non-Hispanic (NH) whites, blacks and Hispanics are more likely to undergo amputation and less likely to undergo bypass surgery for limb salvage. Endovascular procedures are being increasingly performed as first line of therapy for PAD. In this study, we examined the outcomes of endovascular PAD treatments based on race/ethnicity in a contemporary large population-based study. We used Patient Discharge Data (PDD) from California's Office of Statewide Health Planning and Development (OSHPD) to identify all patients over the age of 35 who underwent a lower extremity arterial intervention from 2005 to 2009. A look-back period of five years was used to exclude all patients with prior lower extremity arterial revascularization procedures or major amputation. Cox proportional hazards regression [1] was used to compare amputation-free survival and time to death within 365 days. Logistic regression was used for comparison of 1-month myocardial infarction (MI), 1-month major amputation, 1-month all-cause mortality, 12-month major amputation, 12-month reintervention, and 12-month all-cause mortality rates among NH white, black, and Hispanic patients. These analyses were adjusted for age, gender, insurance status, severity of PAD, comorbidities, history of coronary artery angioplasty or bypass surgery, or history of carotid endarterectomy. Between 2005 and 2009, a total of 41,507 individuals underwent PAD interventions, 25,635 (61.7%) of whom underwent endovascular procedures. There were 17,433 (68%) NH whites, 4,417 (17.2%) Hispanics, 1,979 (7.7%) blacks, 1,163 (4.5%) Asian/Native Hawaiians, and 643 (2.5%) others in this group. There was a statistically significant difference in the amputation-free survival within 365 days among the NH white, Hispanic and black groups (P < 0.0001); the hazard ratio for amputation within 365 days was 1.69 in Hispanics (95% CI 1.51-1.90; P<0.0001) and 1.68 in blacks (95% CI 1.44-1.96; P<0.001) compared to NH whites following endovascular procedures after adjusting for age, gender, insurance status, comorbidities, severity of PAD, history of coronary artery angioplasty or bypass surgery, or history of carotid endarterectomy. After adjusting for the aforementioned confounders, the first reintervention within 12 months was also significantly associated with race/ethnicity (P=0.002). Odds ratio for reintervention was 1.17 in blacks (95% CI 1.06-1.30, P=0.002) and 1.084 in Hispanics (95% CI 1.00-1.16, P=0.04) compared to NH whites. In this contemporary large population-based study, we demonstrated that even among matched cohorts Hispanics and blacks have worse amputation-free survival than NH whites following endovascular therapy. Our study also found that Hispanics and blacks are more likely to undergo lower extremity arterial reinterventions than NH whites. Further research is crucial in understanding if higher reintervention rates in Hispanics and blacks are due to more severe disease and/or poor access to proper follow-up care and optimal medical management. Copyright © 2015 Elsevier Inc. All rights reserved.
    No preview · Article · Mar 2015 · Annals of Vascular Surgery
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    ABSTRACT: Postictal pulmonary edema (PPE) is almost invariably present in human and animal cases of sudden unexpected death in epilepsy (SUDEP) coming to autopsy. PPE may be a contributing factor in SUDEP. The incidence of postictal PPE is unknown. We retrospectively investigated PPE following generalized tonic clonic seizures (GTCS) in the epilepsy monitoring unit. Chest X-Rays (CXR) following each GTCS were obtained in 24 consecutive patients. Relationship of CXR abnormality to seizure duration, ictal/postictal oxygen desaturation (SpO2), apnea and presence of postictal generalized EEG suppression (PGES) was investigated using logistic regression. Eleven of 24 patients had CXR abnormalities following a GTCS. In these 11 patients, 22 CXR were obtained and abnormalities were present in 15 CXR. Abnormalities included PPE in 7 patients, of which 2 also had focal infiltrates. In 4 patients focal infiltrates were present without PPE. There was no significant difference in mean time to CXR (225 min) following GTCS in the abnormal CXR group versus the normal group of patients (196 min). Mean preceding seizure duration was longer (p=0.002) in GTCS with abnormal CXR (259.7 sec) versus GTCS with normal CXR (101.2 sec). Odds-ratio for CXR abnormality was 20.46 (p=0.006) with seizure duration greater than 100 sec versus less than 100 sec. On multivariable analysis, only the seizure duration was a significant predictor of CXR abnormality (p=0.015). Radiographic abnormalities are not uncommon following GTCS. The presence of CXR abnormality is significantly associated with the duration of the preceding GTCS. Severe, untreated PPE may be relevant to the pathophysiology of SUDEP.
    Full-text · Article · Feb 2015 · Seizure
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    ABSTRACT: Abstract Women who have sex with women (WSW) are a medically underserved population. Data on urologic health in WSW are scant. We hypothesized that the prevalence of urinary symptoms in WSW is similar to population norms and that urinary symptoms in WSW would be associated with known risk factors for urologic problems. WSW were recruited to participate in an internet-based survey via invitations, listserves, and social media. Primary outcome measures were the validated Overactive Bladder Questionnaire (OAB-q) and a single question assessing stress urinary incontinence (SUI). OAB status was dichotomized by OAB-q score (0-8=none/mild; >8=moderate/severe). SUI was dichotomized by single item response (none/little bit of the time=none/mild; sometimes through always=moderate/severe). Ethnodemographic, health, sexuality, and relationship data was also collected. Multivariable logistic regression utilizing 17 factors was performed with SAS V9.2, followed by multivariable analysis with stepwise selection based on the initial analysis (included factors, p<0.25). The final study population consisted of 1,566 adult WSW with mean age 34.6±10.4 years. Moderate/severe OAB was present in 354 (23%) women; 275 (18%) reported moderate /severe SUI. Concomitant OAB and SUI were present in 183 (12%). In multivariable analysis with stepwise selection, OAB symptoms were significantly associated with diabetes, history of urinary tract infection, gynecologic surgery, routine health care, and consultation with a provider regarding urinary symptoms. SUI symptoms were associated with sexual bother. This is the first survey report of prevalence and associations of OAB and SUI in a population of WSW. SUI and OAB were prevalent in WSW. Further attention to urological health in WSW is warranted.
    Full-text · Article · Oct 2014 · Journal of Women's Health
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    ABSTRACT: Increasing studies implicate cancer stem cells (CSCs) as the source of resistance and relapse following conventional cytotoxic therapies. Few studies have examined the response of CSCs to targeted therapies, such as tyrosine kinase inhibitors (TKIs). We hypothesized that TKIs would have differential effects on CSC populations depending on their mechanism of action (anti-proliferative vs. anti-angiogenic). We exposed human sarcoma cell lines to sorafenib, regorafenib, and pazopanib and assessed cell viability and expression of CSC markers (ALDH, CD24, CD44, and CD133). We evaluated survival and CSC phenotype in mice harboring sarcoma metastases after TKI therapy. We exposed dissociated primary sarcoma tumors to sorafenib, regorafenib, and pazopanib, and we used tissue microarray (TMA) and primary sarcoma samples to evaluate the frequency and intensity of CSC markers after neoadjuvant therapy with sorafenib and pazopanib. Parametric and non-parametric statistical analyses were performed as appropriate. After functionally validating the CSC phenotype of ALDHbright sarcoma cells, we observed that sorafenib and regorafenib were cytotoxic to sarcoma cell lines (P < 0.05), with a corresponding 1.4 – 2.8 fold increase in ALDHbright cells from baseline (P < 0.05). In contrast, we observed negligible effects on viability and CSC sub-populations with pazopanib. At low doses, there was progressive CSC enrichment in vitro after longer term exposure to sorafenib although the anti-proliferative effects were attenuated. In vivo, sorafenib improved median survival by 11 days (P < 0.05), but enriched ALDHbright cells 2.5 – 2.8 fold (P < 0.05). Analysis of primary human sarcoma samples revealed direct cytotoxicity following exposure to sorafenib and regorafenib with a corresponding increase in ALDHbright cells (P < 0.05). Again, negligible effects from pazopanib were observed. TMA analysis of archived specimens from sarcoma patients treated with sorafenib demonstrated significant enrichment for ALDHbright cells in the post-treatment resection specimen (P < 0.05), whereas clinical specimens obtained longitudinally from a patient treated with pazopanib showed no enrichment for ALDHbright cells (P > 0.05). Anti-proliferative TKIs appear to enrich for sarcoma CSCs while anti-angiogenic TKIs do not. The rational selection of targeted therapies for sarcoma patients may benefit from an awareness of the differential impact of TKIs on CSC populations.
    Full-text · Article · Oct 2014 · BMC Cancer
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    ABSTRACT: Objectives: To evaluate readmission rates and associated factors to identify potentially preventable readmissions. Background: The decision to penalize hospitals for readmissions is compelling health care systems to develop processes to minimize readmissions. Research to identify preventable readmissions is critical to achieve these goals. Methods: We performed a retrospective review of University HealthSystem Consortium database for cancer patients hospitalized from January 2010 to September 2013. Outcome measures were 7-, 14-, and 30-day readmission rates and readmission diagnoses. Hospital and disease characteristics were evaluated to evaluate relationships with readmission. Results: A total of 2,517,886 patients were hospitalized for cancer treatment. Readmission rates at 7, 14, and 30 days were 2.2%, 3.7%, and 5.6%, respectively. Despite concern that premature hospital discharge may be associated with increased readmissions, a shorter initial length of stay predicted lower readmission rates. Furthermore, high-volume centers and designated cancer centers had higher readmission rates. Evaluating institutional data (N = 2517 patients) demonstrated that factors associated with higher readmission rates include discharge from a medical service, site of malignancy, and emergency primary admission. When examining readmission within 7 days for surgical services, the most common readmission diagnoses were infectious causes (46.3%), nausea/vomiting/dehydration (26.8%), and pain (6.1%). Conclusions: A minority of patients after hospitalization for cancer-related therapy are readmitted with potentially preventable conditions such as nausea, vomiting, dehydration, and pain. However, most factors associated with readmission cannot be modified. In addition, high-volume centers and designated cancer centers have higher readmission rates, which may indicate that readmission rates may not be an appropriate marker for quality improvement.
    No preview · Article · Oct 2014 · Annals of Surgery
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    ABSTRACT: Background: With increasing longevity, a growing proportion of patients who present with lower extremity peripheral arterial disease (LE-PAD) are ≥80 years old. While smoking and diabetes mellitus (DM) have traditionally been the main risk factors associated with PAD, we noted a pattern of severe infrapopliteal PAD in patients ≥80 years old in the absence of these traditional risk factors. As recognition of patterns of disease affects decisions regarding diagnostic and therapeutic approach, we sought to confirm this observation. Methods: A single-center retrospective review was performed on all patients who underwent lower extremity arteriography between March 2007 and September 2009. Arteriograms were scored in a blinded fashion. Any infrapopliteal PAD was defined as one or more infrapopliteal arteries with either >50% stenosis or total occlusion. Severe infrapopliteal PAD was defined as 2 or more infrapopliteal arteries with >50% stenosis or total occlusion. Fisher's exact test and 2-sample t-test or Wilcoxon rank-sum test were used for analysis. Results: Two hundred ninety-seven patients comprised the study population. Eighty-two percent (= 145/176) of those ≤70 years old versus 96% (= 46/48) of those ≥80 years old had any infrapopliteal PAD (P = 0.02). Thirty percent of patients ≥80 years old with infrapopliteal PAD had no history of DM or smoking, while only 5% of younger patients had infrapopliteal PAD in the absence of DM or smoking (P < 0.0001). A similar pattern was seen for severe infrapopliteal PAD. Tissue loss was an indication for lower extremity arteriography in 45% of those ≤70 years of age versus 65% of those ≥80 (P = 0.022). Conclusions: A significant proportion of patients ≥80 years of age with PAD develop arterial disease in the infrapopliteal pattern in the absence of the traditional risk factors of smoking and DM. Our data also showed that this pattern of disease is significantly associated with tissue loss and critical limb ischemia, particularly in patients ≥80 years of age. Primary care providers need to be educated to suspect ischemic etiology for foot pain and ulcers in elderly patients not otherwise thought to have risk factors associated with PAD. Vascular specialists need to anticipate this pattern of disease when planning interventions. As smoking becomes less prevalent and as the population ages, octogenarians with severe infrapopliteal arterial occlusive disease will become a larger proportion of the patients treated by vascular specialists.
    No preview · Article · Oct 2014 · Annals of Vascular Surgery
  • David Boudreault · Chin-Shang Li · Michael S Wong

    No preview · Article · Mar 2014 · Plastic and Reconstructive Surgery
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    ABSTRACT: Despite effective local therapy with surgery and radiotherapy (RT), ~50 % of patients with high-grade soft tissue sarcoma (STS) will relapse and die of disease. Since experimental data suggest a significant synergistic effect when antiangiogenic targeted therapies such as sorafenib are combined with RT, we chose to evaluate preoperative combined modality sorafenib and conformal RT in a phase I/II trial among patients with extremity STS amenable to treatment with curative intent. For the phase I trial, eight patients with intermediate- or high-grade STS >5 cm in maximal dimension or low-grade STS >8 cm in maximal dimension received concomitant sorafenib (dose escalation cohort 1:200 twice daily, cohort 2:200/400 daily) and preoperative RT (50 Gy in 25 fractions). Sorafenib was continued during the entire period of RT as tolerated. Surgical resection was completed 4-6 weeks following completion of neoadjuvant sorafenib/RT. Three sorafenib dose levels were planned. Primary endpoints of the phase I trial were maximal tolerated dose and dose-limiting toxicity (DLT). Eight patients were enrolled in the phase I (five females, median age 44 years, two high-grade pleomorphic, two myxoid/round cell liposarcoma, four other). Median tumor size was 16 cm (range 8-29), and all tumors were located in the lower extremity. Two of five patients treated at dose level 2 developed DLT consisting of grade 3 rash not tolerating drug reintroduction. Other grade 3 side effects included anemia, perirectal abscess, and supraventricular tachycardia. Radiation toxicity (grade 1 or 2 dermatitis; N = 8) and post-surgical complications (three grade 3 wound complications) were comparable to historical controls and other series of preoperative RT monotherapy. Complete pathologic reponse (≥95 % tumor necrosis) was observed in three patients (38 %). Neoadjuvant sorafenib in combination with RT is tolerable and appears to demonstrate activity in locally advanced extremity STS. Further study to determine efficacy at dose level 1 is warranted. ( identifier NCT00805727).
    No preview · Article · Feb 2014 · Annals of Surgical Oncology
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    Huijun Han · Philip H Kass · Barth L Wilsey · Chin-Shang Li
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    ABSTRACT: To examine the age and gender-specific trends of Schedule II opioid use among California residents, with special reference to multiple provider users (doctor shoppers). Utilizing data from the California Prescription Drug Monitoring Program, we examined age and gender-specific trends of Schedule II opioid use during calendar years 1999-2007. Specifically, we analyzed the following: (1) the prevalence of Schedule II opioid users among California's population and (2) the proportion of these opioid users who were doctor shoppers (defined as an individual who used more than five different prescribers for all Schedule II opioids he or she obtained in a calendar year). Among all age and gender groups, the prevalence of Schedule II opioid users in California increased by 150%-280% and the prevalence of doctor shoppers among users increased by 111%-213% over 9 years. The prevalence of opioid users was lowest among 18-44 year old men (1.25%) and highest among 65-year and older women (5.31%) by 2007. The prevalence of doctor shoppers was approximately 1.4% among those up to age 64 years and 0.5% among those 65 years and older. The gender difference in doctor shoppers among all age groups was negligible. On average, the cumulative morphine-equivalent amount of Schedule II opioid per individual obtained per year was threefold to sixfold higher for doctor shoppers than for the general population across different age and gender groups. Age and gender differences in opioid use were relatively small, whereas the trends for use of opioids and multiple providers grew at a disquieting rate. Copyright © 2013 John Wiley & Sons, Ltd.
    Full-text · Article · Jan 2014 · Pharmacoepidemiology and Drug Safety
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    ABSTRACT: A majority of individuals infected with human immunodeficiency virus (HIV) have inadequate access to antiretroviral therapy and ultimately develop debilitating oral infections that often correlate with disease progression. Due to the impracticalities of conducting host-microbe systems-based studies in HIV infected patients, we have evaluated the potential of simian immunodeficiency virus (SIV) infected rhesus macaques to serve as a non-human primate model for oral manifestations of HIV disease. We present the first description of the rhesus macaque oral microbiota and show that a mixture of human commensal bacteria and ''macaque versions'' of human commensals colonize the tongue dorsum and dental plaque. Our findings indicate that SIV infection results in chronic activation of antiviral and inflammatory responses in the tongue mucosa that may collectively lead to repression of epithelial development and impact the microbiome. In addition, we show that dysbiosis of the lingual microbiome in SIV infection is characterized by outgrowth of Gemella morbillorum that may result from impaired macrophage function. Finally, we provide evidence that the increased capacity of opportunistic pathogens (e.g. E. coli) to colonize the microbiome is associated with reduced production of antimicrobial peptides.
    Full-text · Dataset · Nov 2013

Publication Stats

790 Citations
214.38 Total Impact Points


  • 2008-2015
    • University of California, Davis
      • Department of Public Health Sciences
      Davis, California, United States
  • 2010-2013
    • California State University, Sacramento
      Sacramento, California, United States