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Biomedical subjects

Rui Li

Publications and source records attributed to Rui Li.

At least 109 records · Page 6Linked to original sources

The alignment and blending of payment incentives within physician organizations.

OBJECTIVE: To analyze the blend of retrospective (fee-for-service, productivity-based salary) and prospective (capitation, nonproductivity-based salary) methods for compensating individual physicians within medical groups and independent practice associations (IPAs) and the influence of managed care on the compensation blend used by these physician organizations. DATA SOURCES: Of the 1,587 medical groups and IPAs with 20 or more physicians in the United States, 1,104 responded to a one-hour telephone survey, with 627 providing detailed information on physician payment methods. STUDY DESIGN: We calculated the distribution of compensation methods for primary care and specialty physicians, separately, in both medical groups and IPAs. Multivariate regression methods were used to analyze the influence of market and organizational factors on the payment method developed by physician organizations for individual physicians. PRINCIPAL FINDINGS: Within physician organizations, approximately one-quarter of physicians are paid on a purely retrospective (fee-for-service) basis, approximately one-quarter are paid on a purely prospective (capitation, nonproductivity-based salary) basis, and approximately one-half on blends of retrospective and prospective methods. Medical groups and IPAs in heavily penetrated managed care markets are significantly less likely to pay their individual physicians based on fee-for-service than are organizations in less heavily penetrated markets. CONCLUSIONS: Physician organizations rely on a wide range of prospective, retrospective, and blended payment methods and seek to align the incentives faced by individual physicians with the market incentives faced by the physician organization.

Capitation Fee↗

Phantom validation of coregistration of PET and CT for image-guided radiotherapy.

Radiotherapy treatment planning integrating positron emission tomography (PET) and computerized tomography (CT) is rapidly gaining acceptance in the clinical setting. Although hybrid systems are available, often the planning CT is acquired on a dedicated system separate from the PET scanner. A limiting factor to using PET data becomes the accuracy of the CT/PET registration. In this work, we use phantom and patient validation to demonstrate a general method for assessing the accuracy of CT/PET image registration and apply it to two multi-modality image registration programs. An IAEA (International Atomic Energy Association) brain phantom and an anthropomorphic head phantom were used. Internal volumes and externally mounted fiducial markers were filled with CT contrast and 18F-fluorodeoxyglucose (FDG). CT, PET emission, and PET transmission images were acquired and registered using two different image registration algorithms. CT/PET Fusion (GE Medical Systems, Milwaukee, WI) is commercially available and uses a semi-automated initial step followed by manual adjustment. Automatic Mutual Information-based Registration (AMIR), developed at our institution, is fully automated and exhibits no variation between repeated registrations. Registration was performed using distinct phantom structures; assessment of accuracy was determined from registration of the calculated centroids of a set of fiducial markers. By comparing structure-based registration with fiducial-based registration, target registration error (TRE) was computed at each point in a three-dimensional (3D) grid that spans the image volume. Identical methods were also applied to patient data to assess CT/PET registration accuracy. Accuracy was calculated as the mean with standard deviation of the TRE for every point in the 3D grid. Overall TRE values for the IAEA brain phantom are: CT/PET Fusion = 1.71 +/- 0.62 mm, AMIR = 1.13 +/- 0.53 mm; overall TRE values for the anthropomorphic head phantom are: CT/PET Fusion = 1.66 +/- 0.53 mm, AMIR = 1.15 +/- 0.48 mm. Precision (repeatability by a single user) measured for CT/PET Fusion: IAEA phantom = 1.59 +/- 0.67 mm and anthropomorphic head phantom = 1.63 +/- 0.52 mm. (AMIR has exact precision and so no measurements are necessary.) One sample patient demonstrated the following accuracy results: CT/PET Fusion = 3.89 +/- 1.61 mm, AMIR = 2.86 +/- 0.60 mm. Semi-automatic and automatic image registration methods may be used to facilitate incorporation of PET data into radiotherapy treatment planning in relatively rigid anatomic sites, such as head and neck. The overall accuracies in phantom and patient images are < 2 mm and < 4 mm, respectively, using either registration algorithm. Registration accuracy may decrease, however, as distance from the initial registration points (CT/PET fusion) or center of the image (AMIR) increases. Additional information provided by PET may improve dose coverage to active tumor subregions and hence tumor control. This study shows that the accuracy obtained by image registration with these two methods is well suited for image-guided radiotherapy.

Algorithms↗

Treatment of hematologic malignancies with alternate hemibody irradiation combined with high-dose chemotherapy: a single-center experience.

The objective of this study was to evaluate the clinical outcome of the treatment of hematologic malignancies with alternate hemibody irradiation (AHBI) combined with high-dose chemotherapy. Seventeen patients with hematologic malignancies were treated with AHBI combined with high-dose chemotherapy. Following high-dose chemotherapy, upper hemibody irradiation (UHBI) and lower hemibody irradiation (LHBI) were given sequentially in a dose of 6 to 9 Gy. UHBI was given 14 days (range, 12-22 days) after high-dose chemotherapy, and LHBI was performed 23 days (range, 7-34 days) after UHBI. Meanwhile, we treated a control group of 14 patients with acute lymphoblastic leukemia (ALL) with autologous hematopoietic stem cell transplantation (AHSCT). Hematopoietic reconstitution was observed in all of the patients. The median follow-up period was 927 days (range, 428-1446 days). The 3-year probabilities of disease-free survival (DFS) were 52.38% +/- 13.47% for the patients in complete remission who underwent AHBI. No patient died of AHBI-related toxicity. The 3-year DFS rates for the 2 groups of patients with ALL were not significantly different (47.73% +/- 17.55% in the AHBI group and 53.88% +/- 14.08% in the AHSCT group; P > .05). AHBI combined with high-dose chemotherapy is a feasible approach for patients with hematologic malignancies and has the advantages of a desirable effectiveness, low costs, simple operation, and acceptable side effects.

Adolescent↗

Organizational factors affecting the adoption of diabetes care management processes in physician organizations.

OBJECTIVE: To describe the extent of adoption of diabetes care management processes in physician organizations in the U.S. and to investigate the organizational factors that affect the adoption of diabetes care management processes. RESEARCH DESIGN AND METHODS: Data are derived from the National Survey of Physician Organizations and the Management of Chronic Illness, conducted in 2000-2001. A total of 1,104 of the 1,590 physician organizations identified responded to the survey. The extent of adoption of four diabetes care management processes is measured by an index consisting of the organization's use of diabetic patient registries, clinical practice guidelines, case management, and physician feedback. The ordinary least-squares model is used to determine the association of organizational characteristics with the adoption of diabetes care management processes in physician organizations. A logistic regression model is used to determine the association of organizational characteristics with the adoption of individual diabetes care management processes. RESULTS: Of the 987 physician organizations studied that treat patients with diabetes, 48% either do not use any or use only one of the four diabetes care management processes. A total of 20% use two care management processes, and 32% use three or four processes. External incentives to improve quality, computerized clinical information systems, and ownership by hospitals or health maintenance organizations are strongly associated with the diabetes care management index and the adoption of individual diabetes care management processes. CONCLUSIONS: Policies to encourage external incentives to improve quality and to facilitate the adoption of computerized clinical information technology may promote greater use of diabetes care management processes.

Chronic Disease↗

Analysis of the quality of coding for tumors in line with International Classification of Diseases.

OBJECTIVE: To find a method for improving the quality of coding for malignant tumors according to the International Classification of Diseases (ICD) and explore the feasibility and necessity of such a method. METHODS: The author collected 26,922 tumor cases and analyzed the matches of the codes for the position of tumors (C code) and the modality of tumors (M code). On the basis of searching result, mistakes in the coding were identified and the causes for these errors explored. RESULTS AND CONCLUSION: Altogether 5,329 mistakes occurred in relation to the arrangement of C code and M code for various and complicated reasons, accounting for 19.79% among the cohort of cases investigated. The present methodology for the coding needs to be improved and better alternatives are possible on the basis of current technology.

Humans↗

Differences in coronary microvascular lesions in coronary heart disease and hypertension: an autopsy study of elderly patients.

BACKGROUND: In the case of hypertension, lesions in the microvessels of the target organs precede and deteriorate further after arteriosclerosis in the small arteries. Thus coronary microvascular lesion (CML) was considered the crucial factor contributing to damage to the target organs. The purpose of this study is to observe the characteristics and differences of CML in autopsies of elderly patients with essential hypertension (EHT), coronary heart disease (CHD), or EHT with CHD, given the same degree of left ventricular wall thickness (LVWT). METHODS: A retrospective study was performed on 246 cases of patients over 60 years old with EHT, CHD, or EHT with CHD, and on 26 cases without cardiovascular disease as controls, out of a total of 3195 consecutive autopsied cases. The arterioles (with diameter 10 - 60 microm) and the capillaries in the cardiac muscle layer were examined by haematoxylin and eosin staining, elastic van Gieson staining, and CD31 immunohistochemistry. To quantify CML severity, measurements were taken of arteriole density (AD), the ratio of wall-to-lumen area of arteriole (RWL), and capillary density (CD), using light microscopy and computer image analysis. Based on LVWT, the cases were divided into four degrees, from I to IV. The EHT, CHD, and EHT with CHD groups all rated LVWT I-IV, and the control group rated LVWT I. SAS software was used for statistical analysis. RESULTS: With the aggravation of LVWT, both AD and RWL increased while CD decreased significantly in the EHT group (P < 0.05 - 0.0001); there were similar but more severe changes in the EHT with CHD group (P < 0.001 - 0.0001); and AD increased (P < 0.001) while RWL and CD did not change significantly in the CHD group. CONCLUSION: Comparing EHT with CHD patients, there are similar patterns of change to AD, but different patterns of change to RWL and CD. CML is much more severe in EHT patients with CHD. We conclude that CML is one of the main causes of decreased coronary flow reserve and myocardial damage in both EHT patients and EHT patients with CHD.

Aged↗

[Measuring the shelf life of CPDA and ACD whole blood stored at above 4 degrees C in vitro].

In order to measure the shelf life of whole blood stored at above 4 degrees C and provide experimental data for blood preservation and transportation in battle fields, 200 ml whole blood was collected from each of the 10 donors and anticoagulated by CPDA or ACD, then 50 ml whole blood was separated from each one and marked as control group, the rest was marked as test group. The control group was stored at 4 degrees C and RBC ATP concentrations was measured at the end of its shelf life which signed as critical ATP. The test group was stored at above 4 degrees C condition, some items as ATP, FHb (free hemoglobin), serum K(+) and germiculture were tested daily and ensured all of them eligible. When RBC ATP decreased to the level of critical ATP, the time of preservation was considered as shelf life. The results showed that at temperatures from 10 to 33 degrees C, the shelf life of CPDA whole blood ranges from 2.5 days to 18 days, while shelf life of ACD whole blood ranges from 1 day to 13 days. It is concluded that CPDA whole blood stored at above 4 degrees C condition can be sent to the front hospital in effective shelf life so that the wounded can be cured in time.

Adenosine Triphosphate↗

[Preliminary study on alternative half body irradiation in the treatment of hematological malignancies].

OBJECTIVE: To evaluate the curative effect of alternative half body irradiation (AHBI) in the treatment of hematological malignancies. METHODS: Seventeen patients with hematological malignancies in complete remission received a high-dose chemotherapy, followed by a two-step AHBI on day 14 (12 approximately 22), upper (UHBI) and lower half body irradiation (LHBI) were sequentially given with each a single dose of 6 approximately 9 Gy at an interval of 23 (7 approximately 34) days. Fourteen received autologous hematopoietic stem cell transplantation (AHSCT) during the same period were chosen as control. RESULTS: Hematopoiesis recovery was observed in all the AHBI patients. The 3-year disease free survival (DFS) rate and the AHBI-related mortality were (52.38 +/- 13.47)% and 0, respectively. The longest survival time was 1446 days with a median follow-up period of 927 (428 approximately 1446) days. The 3-year DFS for the 11 acute lymphocytic leukemia (ALL) patients was (47.73 +/- 17.55)%. By contrast, the 3-year DFS and the AHSCT-related mortality for the 14 ALL patients in the control AHSCT group were (53.88 +/- 14.08)% and 14%, respectively. There was no significant difference in 3-year DFS between AHBI and AHSCT ALL patients. CONCLUSIONS: AHBI provides a feasible approach for hematological malignancy patients.

Adolescent↗

[Study on the formaldehyde-induced DNA damage with comet assay].

Formaldehyde is known as a genotoxic substance. Numerous studies have shown that formaldehyde could induce DNA-DNA and DNA-protein crosslinks. However, scholars have disagreed with each other on the formaldehyde-induced DNA strand breaks. We chose buccal cells as materials to evaluate the genotoxicity of formaldehyde with comet assay--especially for DNA strand breaks. The results showed that formaldehyde of low concentration induced DNA strand breaks, while formaldehyde of high concentration induced DNA-DNA and DNA-protein crosslinks. According to our experimental results, we proposed the concept of the "peak point of break" at which formaldehyde induced DNA strand breaks most.

Comet Assay↗

Programmed cell death in wheat during starchy endosperm development.

The starchy endosperm of wheat underwent programmed cell death (PCD) during its development. It showed a ladder of DNA fragments in multiples of 180-200 bp at specific stages when analyzed by agarose gel electrophoresis. The onset of internucleosomal fragmentation of the genome in wheat endosperm could be accelerated by ethylene. While treatment with abscisic acid (ABA) did not delay the onset of DNA fragmentation, but reduced its extent in developing wheat endosperm. During PCD, beside some ultrastructural changes common to other animal and plant apoptotic cells, the starchy endosperm cells also showed some peculiar ultrastructural features. For example, the chromatins in the nucleoplasm were densely aggregated, only a few condensed chromatins abutted onto the inner surface of the nuclear envelope; the nucleus was the first to suffer from degeneration; during nuclear disintegration a large number of organelles could still be observed in the cytoplasm; after nuclear disintegration, the cell remained alive, and synthesis and accumulation of starches and proteins were carried out as usual in the cytoplasm until the starchy endosperm cell died when it was filled with reserves; no formation of apoptotic bodies could be found and the dead starchy endosperm cell served as a reservoir. The PCD of starchy endosperm cells in wheat was a special form of PCD.

Abscisic Acid↗

Incidence of lipoatrophy and lipohypertrophy in the women's interagency HIV study.

OBJECTIVE: To estimate the incidence of lipoatrophy and lipohypertrophy among HIV-infected and HIV-uninfected women from the Women's Interagency HIV Study. DESIGN: Eight hundred fifteen women with semiannual data on self-report of bidirectional change in body fat, anthropometric measurements, weight, and bioelectric impedance analysis were included in a 30-month incidence analysis. METHODS: Lipoatrophy and lipohypertrophy in both peripheral (arms, legs, and buttocks) and central (waist, chest, and upper back) sites were defined by self-report of either a decrease or an increase in a body fat region over the previous 6 months that was confirmed by a corresponding change in anthropometric measurement. RESULTS: Weight and total body fat increased in HIV-uninfected women but remained stable in HIV-infected women over 30 months. Among HIV-infected women, the incidence of peripheral (relative hazard, 2.1; 95% confidence interval [CI], 1.4-3.3) and central (relative hazard, 1.9; 95% CI, 1.2-2.8) lipoatrophy was about double that among HIV-uninfected women, after adjustment for age and race. The incidence of peripheral lipohypertrophy appeared lower among HIV-infected women than among HIV-uninfected women (relative hazard, 0.8; 95% CI, 0.6-1.1), while the incidence of central lipohypertrophy did not differ by HIV status. Of HIV-infected women with 2 of 4 lipodystrophy outcomes, most (81%) had combined peripheral and central lipoatrophy or combined peripheral and central lipohypertrophy. Only 14% of these women had both peripheral lipoatrophy and central lipohypertrophy. CONCLUSIONS: These prospective data suggest that lipoatrophy, affecting both peripheral and central sites, predominates in HIV-infected women. The simultaneous occurrence of peripheral lipoatrophy and central lipohypertrophy was uncommon.

Acquired Immunodeficiency Syndrome↗

Downregulation of ID4 by promoter hypermethylation in gastric adenocarcinoma.

Promoter hypermethylation has become apparent as a common mechanism of gene silencing in cancer. Based on our published microarray expression data, we noticed a prominent downregulation of ID4 in gastric adenocarcinoma. The dense 5' CpG island covering the previously mapped upstream promoter of ID4 has prompted us to relate its downregulation to promoter hypermethylation. ID proteins are distinct members in the helix-loop-helix family of transcriptional regulators, which modulate various key developmental processes. Emerging data have suggested the involvement of ID genes in tumorigenesis. In this study using bisulfite genomic sequencing, we have found hypermethylation of ID4 promoter in most gastric cancer cell lines and 30% of primary tumors. This correlated with decreased level of ID4 expression. Restoration of ID4 expression in various gastric cancer cell lines was achieved by treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine, which at times required the synergistic action of the histone deacetylase inhibitor trichostatin A, but not with trichostatin A alone. Re-expression was accompanied by the corresponding ID4 promoter demethylation. Furthermore, we have found significant association of ID4 promoter methylation with hMLH1 promoter methylation (P=0.008) and microsatellite instability (P=0.006). Overall, our results have shown that transcriptional silencing of ID4 is related to the aberrant methylation of its promoter in gastric cancer. The significant association of ID4 and hMLH1 promoter hypermethylation suggested that ID4 may also be among the genes being targeted in the CpG island methylator phenotype tumorigenic pathway.

Adenocarcinoma↗

Analysis of the immunological microenvironment at the tumor site in patients with non-small cell lung cancer.

BACKGROUND AND AIMS: Inactivation of tumor-infiltrating lymphocytes by immunomodulating cytokines shed by tumor cells into the tumor local microenvironment might be a potential escape strategy of various tumors from immune-immediate killing. Here, we provide an analysis of the cytokine profile at the tumor site in patients with non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Using in situ hybridization (ISH), we determined the mRNA expression in lymphocytes and tumor cells for IL-2, INF-gamma, IL-12 (p40), IL-18, IL-4, IL-10, TGF-beta1, IL-1, IL-3, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF), TNF-alpha, and TGF-alpha in five fresh pleural effusion samples and 18 tumor tissue samples of patients with NSCLC. RESULTS: In pleural effusion as well as in tumor tissue of NSCLC patients, the mRNA expression of IL-4, IL-10, TGF-alpha, and TGF-beta1 was significantly higher than that of IL-2, IL-12, IL-18 and INF-gamma. In contrast, the analysis of tuberculosis pleural effusion samples revealed lower mRNA levels for all cytokines and did not show any significant difference among them. CONCLUSION: The predominant mRNA expression of type II and immunosuppressive cytokines in pleural effusion and tumor tissue of NSCLC patients mirrors an immunosuppressive state in the immunological microenvironment. The present study may, therefore, help to elucidate mechanisms of tumor escape and contribute to the development of an effective immunomodulatory treatment of NSCLC.

Carcinoma, Non-Small-Cell Lung↗

Protein preparation, crystallization and preliminary X-ray crystallographic studies of a thermostable hypoxanthine-guanine phosphoribosyltransferase from Thermoanaerobacter tengcongensis.

Native and His-tagged mutant (L160I) hypoxanthine-guanine phosphoribosyltransferase (HGPRT) from Thermoanaerobacter tengcongensis were cloned, expressed in Escherichia coli and purified. Both proteins were crystallized with polyethylene glycol as the main precipitant at 293 K using the hanging-drop vapour-diffusion method. The crystal of native HGPRT belongs to space group C222(1), with unit-cell parameters a = 65.77, b = 137.73, c = 95.27 A, and diffracted to 2.2 A resolution on an in-house X-ray generator. The crystal of the His-tagged mutant (L160I) HGPRT belongs to the space group I222, with unit-cell parameters a = 52.21, b = 88.36, c = 93.03 A, and diffracted to 1.7 A resolution in-house.

Bacillaceae↗

Impact of HIV infection and HAART on serum lipids in men.

CONTEXT: Alterations in serum lipid values have been widely reported among persons infected with human immunodeficiency virus (HIV) type 1 treated with highly active antiretroviral therapy (HAART), but no data have yet been reported on changes from preseroconversion lipid values. OBJECTIVE: To describe changes in serum cholesterol levels associated with HIV infection and antiretroviral medication exposure, and 1-time assessment of triglyceride levels post-HAART initiation. DESIGN, SETTING, AND PARTICIPANTS: The Multicenter AIDS Cohort Study, a prospective study in which homosexual and bisexual men were enrolled and from which 50 of 517 HIV seroconverters were drawn for the analysis herein, who later initiated HAART, involving measurements of stored serum samples obtained between 1984 and 2002. MAIN OUTCOME MEASURES: Changes in levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) at 6 time points during an average of 12 years; 1-time assessment of triglyceride levels from the third post-HAART clinic visit. RESULTS: Among the 50 men, notable declines in mean serum TC (-30 mg/dL [-0.78 mmol/L]), HDL-C (-12 mg/dL [-0.31 mmol/L]), and LDL-C values (-22 mg/dL [-0.57 mmol/L]) were observed after HIV infection. Following HAART initiation, there were large increases in mean TC and LDL-C values (50 and 21 mg/dL [1.30 and 0.54 mmol/L], respectively); however, the mean changes from the preseroconversion values were 20 mg/dL (0.52 mmol/L) (95% confidence interval [CI], -1 to 41) and -1 mg/dL (-0.03 mmol/L) (95% CI, -25 to 22), respectively. Mean HDL-C remained below baseline levels throughout follow-up. The median value (interquartile range) of triglycerides was 225 mg/dL (2.54 mmol/L) (147-331 mg/dL). CONCLUSIONS: Before treatment, HIV infection results in substantial decreases in serum TC, HDL-C, and LDL-C levels. Subsequent HAART initiation is associated with increases in TC and LDL-C but little change in HDL-C. Increases in TC and LDL-C observed after about 3 years of HAART possibly represent a return to preinfection serum lipid levels after accounting for expected age-related changes.

Adult↗

Active decay of composite excitatory postsynaptic potentials in hippocampal slices from young rats.

NMDA receptor dependent synaptic plasticity was examined in hippocampal slices using a novel pharmacological pairing procedure. Field excitatory postsynaptic potentials (EPSPs) were recorded from the CA1 area of slices maintained in a low Mg(2+) solution using a stimulus rate of 0.1-0.2 Hz. The NMDA receptor antagonist 2-amino-5-phosphonovalerate (AP5) was initially included in the perfusion solution to establish baseline recording of isolated AMPA EPSPs. Washing out AP5 led to the expression of composite EPSPs, containing both AMPA and NMDA receptor mediated components. Following an initial, transient potentiation of the AMPA component, the composite responses gradually decayed for several hours, involving AMPA and NMDA components to a similar extent. This decay was input specific and could be terminated at any stage by reapplication of AP5. Subsequent long-term potentiation (LTP) reversed the effect to an extent inversely related to the degree of depression. Experiments to test the interaction with long-term depression (LTD) revealed a significant but incomplete overlap between the two depression processes. In conclusion, pairing synaptic activation at test stimulus frequency with pharmacological unblocking of NMDA receptors allows for expression of composite EPSPs that decay substantially, due to an active mechanism. The underlying process appears to be at least partly distinct from those involved in homosynaptic LTP and LTD.

Age Factors↗

Variation in gene expression patterns in human gastric cancers.

Gastric cancer is the world's second most common cause of cancer death. We analyzed gene expression patterns in 90 primary gastric cancers, 14 metastatic gastric cancers, and 22 nonneoplastic gastric tissues, using cDNA microarrays representing approximately 30,300 genes. Gastric cancers were distinguished from nonneoplastic gastric tissues by characteristic differences in their gene expression patterns. We found a diversity of gene expression patterns in gastric cancer, reflecting variation in intrinsic properties of tumor and normal cells and variation in the cellular composition of these complex tissues. We identified several genes whose expression levels were significantly correlated with patient survival. The variations in gene expression patterns among cancers in different patients suggest differences in pathogenetic pathways and potential therapeutic strategies.

Adenocarcinoma↗