A bioactive material with dual integrin-targeting ligands regulates specific endogenous cell adhesion and promotes vascularized bone regeneration in adult and fetal bone defects.

Significant progress has been made in designing bone materials capable of directing endogenous cells to promote vascularized bone regeneration. However, current strategies lack regulation of the specific endogenous cell populations for vascularized bone regeneration, thus leading to adverse tissue formation and decreased regenerative efficiency. Here, we engineered a biomaterial to regulate endogenous cell adhesion and promote vascularized bone regeneration. The biomaterial works by presenting two synthetic ligands, LLP2A and LXW7, explicitly targeting integrins α4ß1 and αvß3, respectively, expressed on the surfaces of the cells related to bone formation and vascularization, such as mesenchymal stem cells (MSCs), osteoblasts, endothelial progenitor cells (EPCs), and endothelial cells (ECs). In vitro, the LLP2A/LXW7 modified biomaterial improved the adhesion of MSCs, osteoblasts, EPCs, and ECs via integrin α4ß1 and αvß3, respectively. In an adult rat calvarial bone defect model, the LLP2A/LXW7 modified biomaterial enhanced bone formation and vascularization by synergistically regulating endogenous cells with osteogenic and angiogenic potentials, such as DLX5+ cells, osteocalcin+ cells, CD34+/CD45- cells and CD31+ cells. In a fetal sheep spinal bone defect model, the LLP2A/LXW7 modified biomaterial augmented bone formation and vascularization without any adverse effects. This innovative biomaterial offers an off-the-shelf, easy-to-use, and biologically safe product suitable for vascularized bone regeneration in both fetal and adult disease environments.

Sex-related differences in safety profiles, pharmacokinetics and tissue distribution of sinomenine hydrochloride in rats.

Sinomenine is a bioactive alkaloid isolated from the Chinese medicinal plant Sinomenium acutum (Thunb.) Rehd. et Wils which exhibits significant analgesic, anti-inflammatory, and immunosuppressive effects. Sinomenine hydrochloride (SH) preparations, classified as natural disease-modifying antirheumatic drugs, are currently available for the treatment of rheumatoid arthritis and other rheumatic diseases. Our toxicity evaluation demonstrated that the median lethal dose of SH in female Sprague-Dawley (SD) rats was over 11 times greater than that in male SD rats, revealing striking sex-linked differences in the safety profile of SH. The present study was designed to investigate differences in the pharmacokinetics (PKs) and tissue distribution of SH between male and female SD rats after a single oral dose of 25 mg/kg. PK and tissue distribution studies were performed using a validated UPLC-MS/MS method. The results showed that SH-treated SD female rats displayed markedly greater drug exposure, and SH exhibited a longer half-life and slower clearance rate than comparable studies in male rats. Moreover, the tissue distribution study confirmed that the sinomenine concentration in female rats was considerably greater in the internal organs than in male rats. Our study demonstrates, for the first time, significant sex-related differences in the safety profile and PKs of SH, which may be associated with a distinct sex-dependent metabolic mechanism of sinomenine.

[In Vitro Fatigue Test of Lung Volume Reduction Loop].

Lung volume reduction loop uses bronchoscopic lung volume reduction(BLVR) technology to compress and collapse the necrotic emphysema tissue and exhaust the internal gas to achieve the purpose of lung volume reduction to treat emphysema. After the lung volume reduction loop is implanted into the human body, the compressed part of the lung tissue tends to expand with breathing, which makes the lung volume reduction loop expand into a linear trend periodically. Fatigue resistance is one of the most important performance indexes of the lung volume reduction loop. In the paper, Z-direction vibration fatigue machine was used to simulate the changes of human respiratory cycle movement to test the fatigue performance of lung volume reduction loop, which can provide some reference for the test method of in vitro fatigue performance of lung volume reduction related products in the future.

Surgical Outcomes After Neoadjuvant Chemoimmunotherapy for Resectable Non-Small Cell Lung Cancer.

BACKGROUND: Neoadjuvant chemoimmunotherapy for resectable non-small cell lung cancer (NSCLC) represents an important research topic. Despite the potential benefits of this approach, the inflammatory responses and adverse events associated with neoadjuvant chemoimmunotherapy can present technical challenges and compromise a planned resection. This study assessed the safety and feasibility of neoadjuvant chemoimmunotherapy followed by surgery for resectable NSCLC. METHODS: The study was conducted from May 2019 to March 2021. Patients who were age 18 years or older, were diagnosed with stage Ib-IIIb NSCLC, and received neoadjuvant chemoimmunotherapy followed by surgery were included. Demographic information, clinical and pathologic characteristics, data about neoadjuvant therapy, and surgical details were collected by retrospective chart review. Toxicity profiles were collected retrospectively or by telephone follow-up. RESULTS: Twenty patients were included in this study. The median age was 56 years (range, 48-72 years), and 18 patients (90%) were men. Squamous carcinoma (14/20, 70%) was the most common cancer type, followed by adenocarcinoma (4/20, 20%), adenosquamous carcinoma (1/20, 5%), and large cell neuroendocrine carcinoma (1/20, 5%). All patients received two to four cycles of neoadjuvant therapy, and the median interval between final therapy and surgery was 49 days (range, 23-133 days). Computed tomography evaluation after neoadjuvant therapy showed partial response in 15 patients (75%) and stable disease in 5 (25%). Final pathologic examinations showed major pathologic response in eight patients, including pathologic complete response in five (25%). Most patients (18/20, 90%) had reduced pathologic staging. Twelve patients (60%) underwent open thoracotomy; the other eight patients underwent minimally invasive surgery, which was uneventful and without intraoperative conversion to open thoracotomy. No perioperative deaths occurred, and only seven patients (35%) developed postoperative complications. Most patients experienced only grade 1-2 adverse effects and laboratory abnormalities during neoadjuvant therapy, and no grade 3 or worse adverse effects or laboratory abnormalities occurred. No patients experienced surgical delays as a result of immune-related adverse events. CONCLUSIONS: Preoperative administration of chemoimmunotherapy for patients with resectable NSCLC was safe and feasible.

The clinical and radiological characteristics of pulmonary cryptococcosis in immunocompetent and immunocompromised patients.

BACKGROUND: We characterized the clinical features, radiographic characteristics, and response to treatment of immunocompetent and immunocompromised patients with pulmonary cryptococcosis (PC). METHODS: We retrospectively reviewed the medical records and radiological profiles of patients diagnosed with PC who received surgical resection between May 2015 and November 2020 in a tertiary referral center. RESULTS: A total of 21 males and 18 females were included in the study. 23 patients were immunocompetent and 20 out of the 39 were asymptomatic. Immunocompetent patients were diagnosed with PC at a younger age than immunocompromised patients (48.9 vs 57.1 years, P = 0.02). Single nodule pattern was the most frequent lesion pattern (33 out of 39, 84.6%) and right upper lobe was the most common site of location (15 out of 47, 31.9%). The majority of lesions were located peripherally (38 out of 47, 80.9%) and most lesions were 1-2 cm in diameter (30 out of 47, 63.8%). Cavitation was more likely to occur in immunocompromised patients (5 out of 11, 45.5%) than in immunocompetent patients (6 out of 36, 16.7%) (P = 0.04) and there was complete resolution of PC in all patients treated with anti-fungal therapy. CONCLUSIONS: Immunocompetent patients were diagnosed with PC at a younger age than immunocompromised patients. Single nodule pattern was the most frequent lesion pattern in PC patients. Cavitation was more likely to occur in immunocompromised patients than in immunocompetent patients.

Exosomal Delivery of FTO Confers Gefitinib Resistance to Recipient Cells through ABCC10 Regulation in an m6A-dependent Manner.

Gefitinib is suitable for the treatment of locally advanced or metastatic non-small cell lung cancer. However, the development of acquired resistance limits its long-term efficacy in regardless of significant clinical benefit to patients. Therefore, to elucidate the mechanism of gefitinib resistance in addition to target gene mutation may greatly increase its clinical efficacy. It was found first that N 6-methyladenosine RNA demethylase FTO was significantly enriched in serum exosomes of gefitinib-resistant (GR) patients compared with that of gefitinib-sensitive (GS) patients through exosomal RNA sequencing. Meanwhile, the average m6A proportion in GR patients was significantly lower when compared with that in GS patients. Besides, GR cell-derived exosome internalization attenuated the total m6A abundance and gefitinib sensitivity of PC9 cells. Not only FTO knockdown enhanced the gefitinib sensitivity of GR cells but also FTO reduction in donor exosomes alleviated the acquired resistance of recipient PC9 cells. GR cell-derived exosomal-FTO promoted ABCC10 of recipient cells in a m6A-dependent manner. FTO/YTHDF2/ABCC10 axis played a role in intercellular transmission of GR cell-derived exosome-mediated gefitinib resistance both in vitro and in vivo. In general, this research showed that m6A modification was involved in the decrease of gefitinib sensitivity. GR cell-derived exosomes could decrease gefitinib sensitivity of recipient cells in exosomal delivery of FTO-dependent manner. FTO/YTHDF2/ABCC10 axis played a role in intercellular transmission of GR cell-derived exosome-mediated gefitinib resistance. IMPLICATIONS: Our results elucidated another potential molecular mechanism of gefitinib resistance in non-small cell lung cancer besides secondary EGFR mutations.

Sea-level rise will reduce net CO2 uptake in subtropical coastal marshes.

Coastal marshes have a significant capacity to sequester carbon; however, sea-level rise (SLR) is expected to result in prolonged flooding and saltwater intrusion in coastal regions. To explore the effects of SLR projections on net CO2 uptake in coastal marshes, we conducted a "double-check" investigation, including the eddy covariance (EC) measurements of the CO2 fluxes in subtropical coastal marshes along inundation and salinity gradients, in combination with a mesocosm experiment for analyzing CO2 flux components under waterlogging and increased salinity conditions. During the same measurement periods, the net ecosystem CO2 exchange (NEEEC based on the EC dataset) in an oligohaline marsh was higher than that in a low-elevation mesohaline marsh, whereas the NEEEC was lower than that in a high-elevation freshwater marsh. The declines in NEEEC between the marshes could be attributed to a greater decrease in gross primary production relative to ecosystem respiration. Waterlogging slightly increased the NEEms (NEE based on the mesocosms) because of inhibited soil respiration and slight changes in plant photosynthesis and shoot respiration. However, the NEEms measured during the drainage period decreased significantly due to the stimulated soil respiration. The NEEms decreased with increasing salinity (except under mild salinity), and waterlogging exacerbated the adverse impacts of salinity. The amplificatory effect of decreases in both leaf photosynthesis and growth under hydrological stresses contributed more to reduce the NEEms than to respiratory effluxes. Both waterlogging and increased salinity reduced the root biomass, soil microbial biomass, and activities of assayed soil enzymes (except for cellulase under waterlogging conditions), leading to limited soil respiration. The declines in plant growth, photosynthesis, and soil respiration could also be attributed to the decrease in soil nutrients under waterlogging and increased salinity conditions. We propose that the coupling of SLR-driven hydrological effects lowers the capacity of CO2 uptake in subtropical coastal marshes.

Morphological and digestive adjustments buffer performance: How staging shorebirds cope with severe food declines.

Organisms cope with environmental stressors by behavioral, morphological, and physiological adjustments. Documentation of such adjustments in the wild provides information on the response space in nature and the extent to which behavioral and bodily adjustments lead to appropriate performance effects. Here we studied the morphological and digestive adjustments in a staging population of migrating Great Knots Calidris tenuirostris in response to stark declines in food abundance and quality at the Yalu Jiang estuarine wetland (northern Yellow Sea, China). At Yalu Jiang, from 2011 to 2017 the densities of intertidal mollusks, the food of Great Knots, declined 15-fold. The staple prey of Great Knots shifted from the relatively soft-shelled bivalve Potamocorbula laevis in 2011-2012 to harder-shelled mollusks such as the gastropod Umbonium thomasi in 2016-2017. The crushing of the mollusks in the gizzard would require a threefold to 11-fold increase in break force. This was partially resolved by a 15% increase in gizzard mass which would yield a 32% increase in shell processing capacity. The consumption of harder-shelled mollusks was also accompanied by reliance on regurgitates to excrete unbreakable parts of prey, rather than the usual intestinal voidance of shell fragments as feces. Despite the changes in digestive morphology and strategy, there was still an 85% reduction in intake rate in 2016-2017 compared with 2011-2012. With these morphological and digestive adjustments, the Great Knots remaining faithful to the staging site to a certain extent buffered the disadvantageous effects of dramatic food declines. However, compensation was not complete. Locally, birds will have had to extend foraging time and use a greater daily foraging range. This study offers a perspective on how individual animals may mitigate the effects of environmental change by morphological and digestive strategies and the limits to the response space of long-distance migrating shorebirds in the wild.

MiR-142-3p functions as a potential tumor suppressor directly targeting HMGB1 in non-small-cell lung carcinoma.

BACKGROUND: microRNAs (miRNAs) play a significant role in cancer development and progression by regulating the expression of oncogenes or tumor suppressor genes. Previous study using microarrays demonstrated that miR-142-3p was downregulated in patients with Non-small-cell lung carcinoma (NSCLC). However, the functional role of miR-142-3p in NSCLC is still unclear. MATERIAL AND METHOD: Real-time quantitative PCR was applied to evaluate the expression level of miRNA-142-3p in NSCLC and normal samples. The cell proliferation of NSCLC cells was analyzed by MTT and colony formation assay after miR-142-3p transfection. Luciferase activities assay, cotransfection and Western blot were used to reveal that the predicted target genes of miR-125b were direct and specific. RESULTS: In this study, we demonstrate miR-142-3p was downregulated in NSCLC tissues and cell lines. We demonstrated that the overexpression of miR-142-3p inhibits NSCLC cell proliferation and induced cell apoptosis. Furthermore, we demonstrate HMGB1 was a directly target of miR-142-3p in NSCLC cells, and confirmed the target specificity between miR-142-3p and the HMGB1 3'-untranslated region by luciferase reporter assay. CONCLUSIONS: These results suggest that miR-142-3p may be a tumor suppressor through the downregulation of HMGB1 in NSCLC. miR-142-3p may be a tumor suppressor and a potential therapeutic agent for patients with NSCLC.

Epidemiology of pediatric herpes zoster after varicella infection: a population-based study.

BACKGROUND: There are limited population-based data regarding pediatric herpes zoster (HZ). METHODS: Children aged <12 years with varicella infections between 2000 and 2006 were identified from a national population-based database and followed-up for a diagnosis of HZ until December 2008. Since a routine varicella vaccination program was started in 2004, vaccinated children without medically attended varicella were identified between 2004 and 2006, and followed-up for a diagnosis of HZ until December 2008. RESULTS: Of 27 517 children with medically attended varicella, 428 developed HZ. The incidence of HZ was 262.1 per 100 000 person-years. Of 25 132 vaccinated children without medically attended varicella, 106 developed HZ. The incidence of HZ was 93.3 per 100 000 person-years. The mean duration from varicella to HZ was 4.12 years. Children diagnosed with varicella at aged <2 years had a higher incidence (P < .001) and shorter duration (P = .04) than those diagnosed aged ≧2 years. Children diagnosed with varicella aged ≥2 but <8 years had a significantly increased incidence of HZ after than before the vaccination program (relative risk = 1.85 at 3 years of follow-up, P = .03). Children with varicella infections had a significantly greater risk of HZ than vaccinated children without a history of varicella (relative risk = 2.31 at 4 years of follow-up, P < .001). CONCLUSIONS: This study demonstrates the population-based epidemiologic characteristics of pediatric HZ among those who contracted varicella. In the early postvaricella vaccination period, an increased HZ incidence was observed among children with varicella infection aged ≥2 years.

Nationwide survey to evaluate medical utilization by patients with inguinal hernia and the risk of developing varicocele in Taiwan.

BACKGROUND: The purpose of this study was to analyze age, geographical and seasonal variations in medical service utilization by patients with inguinal hernia in Taiwan, and the influence of herniorrhaphy on development of ipsilateral varicocele in male patients. METHODS: Between 2001 and 2008, comprehensive data on the characteristics of medical service utilization by patients with inguinal hernia was evaluated via a retrospective nationwide population-based study. Data were obtained from the National Health Insurance Research Database in Taiwan. Parameters for comparison included newly diagnosed inguinal hernia cases, number of herniorrhaphies, and incidence rates every year, number of outpatient visits for inguinal hernia, and herniorrhaphy by age, season, and area of Taiwan. RESULTS: There was an average of 1,466 newly diagnosed inguinal hernia cases and 871.9 herniorrhaphies performed per year per million population during the study period. The male ratio for both newly diagnosed inguinal hernia cases and number of herniorrhaphies increased significantly by age. The number of newly diagnosed inguinal hernia cases and outpatient visits for inguinal hernia was highest during summer, followed by spring, autumn, and winter, and in the north of Taiwan, followed by the center, south, and east. Additionally, the incidence of developing ipsilateral varicocele after herniorrhaphy was low in male patients. CONCLUSION: The number of newly diagnosed inguinal hernia cases and outpatient visits for inguinal hernia is highest during summer and lowest in eastern Taiwan. In addition, the incidence of developing ipsilateral varicocele after herniorrhaphy is higher in patients aged 10-19 years.

The fetal frontomaxillary facial angle in normal and trisomy 21 ultrasounds at 11-13(+6) weeks of gestation: findings among the ethnic Chinese compared with Caucasian.

OBJECTIVE: The aim of this research was to compare the fetal frontomaxillary facial (FMF) angle between normal and trisomy 21 fetuses at 11(+0) -13(+6) weeks gestation in a Chinese population. METHODS: A prospective observational study was performed that included 640 euploid and 45 trisomy 21 singleton pregnancies undergoing first trimester ultrasound screening between 11 and 13(+6) weeks of gestation. The FMF angle was measured in the midsagittal plane using the standard technique. RESULTS: The fetal mean FMF angle decreased with the increasing crown-rump length (CRL) from 88.6°at a CRL of 45 mm to 78.5° at a CRL of 84 mm (FMF angle = 100.212 - 0.258 × CRL, R(2) = 0.222, p < 0.001). The overall mean FMF angle in the euploid population was 82.9° ± 4.1° and in trisomy 21 cases, 92.3° ± 5.2°. CONCLUSIONS: Fetal FMF angle is affected by gestational age in a Chinese population, although it remains a significant predictor of fetal trisomy 21.

[Comparison of two rat models of myocardial infarction].

OBJECTIVE: To compare two rat models of myocardial infarction established by coronary artery ligation and harmonic scalpel method for their advantages, disadvantages and applications. METHODS: Sixty Sprague Dawley rats were randomly divided into sham-operated group, coronary artery ligation group and harmonic scalpel group. In the latter two groups, myocardial infarction was induced by ligation of the left anterior descending coronary artery and coagulation of the artery, respectively. Four weeks after the operations, the rats were sacrificed to measure the serum levels of CK, CK-MB, LDH and AST, and the hearts were collected for histopathological observation with HE staining. RESULTS: The rats in the sham-operated group and coronary artery ligation group showed no significant differences in serum levels of CK , CK-MB , LDH or AST. Histologically, the myocardial tissues of the two models all showed coagulation necrosis and inflammatory cell infiltration, with granulation tissue ingrowth in the infracted tissues and scar formation. The mortality rate of the rats in coronary artery ligation group was 50% at 4 weeks, significantly higher than that of the harmonic scalpel group (20%, P<0.05). CONCLUSION: Coronary artery ligation and harmonic scalpel method are both effective means to produce rat models of myocardial infarction. The latter method can establish a more stable model for studying the mechanism and treatment of myocardial infarction.

[Investigation and assessment of damage in earthquake in Yushu, Qinghai based on multi-spectral remote sensing].

The devastating Yushu Earthquake occurred in Qinghai Province, northwest China, with a magnitude of 7.1 on April 14, 2010, which has caused huge destructive losses. Most buildings along the seismic zone were ruined, especially the old and the basic civil structure houses completely destroyed. The earthquake also triggered geological disasters, such as landslides, collapses, debris flows, etc. In the present study, the remote sensing technique was used to assess and analyze the situation of the earthquake damage. There are four classes of feature which can be interpreted according to the remote sensing imageries: (1) the damage degree of buildings, like civilian homes, temples; (2) the field disasters of earthquake, such as ground fissures, landslides, collapses, debris flows, and earthquake subsidence; (3) the damage degree of structures, such as dam; (4) the damage degree of the lifeline, for example, the highway. The features can be obtained according to high spatial resolution of remote sensing imageries, through image processing and interpretation methods. Post-disaster rehabilitation and reconstruction phase should fully consider the regional seismotectonic background and the carrying capacity of resources and environment. With the assessment results of earthquake disaster remote sensing, at last, preliminary suggestions were proposed for the rehabilitation and reconstruction planning of Yushu earthquake.

Using decoy effects to influence an online brand choice: the role of price-quality trade-offs.

This research aims to investigate decoy effects on online brand choices. To assess the influence of decoys, we test decoy effects on three constructs-product involvement, judgment conditions, and decoy conditions-within an online experiment. A survey of 635 Internet users and a 2 × 2 × 3 ANOVA between-subjects experimental design is used to guide the research design and the systematic analysis procedure. A major finding of this study is that a standard decoy seems to have a significant effect on an advertised (target) brand for high-involvement products; from the survey, it is also apparent that competitors can also use inferior decoys to increase brand preference for low-involvement products.

Modified morphology of graphene sheets by Argon-atom bombardment: molecular dynamics simulations.

By a molecular dynamics method, we simulated the process of Argon-atom bombardment on a graphene sheet with 2720 carbon atoms. The results show that, the damage of the bombardment on the graphene sheet depends not only on the incident energy but also on the particle flux density of Argon atoms. To compare and analyze the effect of the incident energy and the particle flux density in the Argon-atom bombardment, we defined the impact factor on graphene sheet by calculating the broken-hole area. The results indicate that, there is an exponential accumulated-damage for the impact of both the incident energy and the particle flux density and there is a critical incident energy ranging from 20-30 eV/atom in Argon-atom bombardment. Different configurations, such as sieve-like and circle-like graphene can be formed by controlling of different particle flux density as the incident energy is more than the critical value. Our results supply a feasible method on fabrication of porous graphene-based materials for gas-storages and molecular sieves, and it also helps to understand the damage mechanism of graphene-based electronic devices under high particle radiation.

[Vegetation water content retrieval and application of drought monitoring using multi-spectral remote sensing].

The vegetation is one of main drying carriers. The change of Vegetation Water Content (VWC) reflects the spatial-temporal distribution of drought situation and the degree of drought. In the present paper, a method of retrieving the VWC based on remote sensing data is introduced and analyzed, including the monitoring theory, vegetation water content indicator and retrieving model. The application was carried out in the region of Southwest China in the spring, 2010. The VWC data was calculated from MODIS data and spatially-temporally analyzed. Combined with the meteorological data from weather stations, the relationship between the EWT and weather data shows that precipitation has impact on the change in vegetation moisture to a certain extent. However, there is a process of delay during the course of vegetation absorbing water. So precipitation has a delaying impact on VWC. Based on the above analysis, the probability of drought monitoring and evaluation based on multi-spectral VWC data was discussed. Through temporal synthesis and combined with auxiliary data (i. e. historical data), it will help overcome the limitation of data itself and enhance the application of drought monitoring and evaluation based on the multi-spectral remote sensing.

[Establishment of patient-derived xenotransplantation models for non-small cell lung cancer in immune deficient mice].

BACKGROUND AND OBJECTIVE: Targeted therapies have become a valuable therapeutic option for cancer. Establishment of different animal tumor models has become necessary. This study was to establish xenotransplantation models for patient-derived non-small cell lung cancer (NSCLC) in immune deficient mice. METHODS: Immune deficient mice, BALB/C-nu, NOD/scid and SCID, 16 in each strain, were used. Sixteen tumor specimens were obtained from patients with NSCLC. Each specimen was subcutaneously transplanted into one mouse from each of the three strains. The tumor formation rate, time to tumor engraftment, tumor volume doubling time were recorded and compared among the three strains of mice. Histology of xenograft tumors was examined. RESULTS: The total tumor formation rate was 75% (12/16). The tumor formation rate was the highest in SCID mice (56.25%). Only four tumors were engrafted in SCID mice, and two in BALB/C-nu mice. The tumor formation rate, time to tumor engraftment, and tumor volume doubling time were not significantly different among the three strains of mice. The incidence of tumor size over 1cm in the upper flanks of the mice (56.25%) was significantly higher than that in the lower flanks (25%) (P=0.037). Haematoxylin Eosin staining revealed a high degree of histological similarity between all xenograft and the parental tumors. CONCLUSIONS: We have established xenotransplantation models for patient-derived NSCLC with a success rate of 75% in BALB/C-nu and SCID mice. The xenograft tumors have the same histological features to those of their parental tumors.

Explaining the race difference in prostate cancer stage at diagnosis.

Prostate cancer is the most frequently diagnosed cancer in males in the United States, accounting for an estimated 186,320 new cases in 2008. There are striking racial or ethnic differences in prostate cancer incidence and mortality rates in the United States, with Black males 1.6 times more likely to be diagnosed and 2.4 times more likely to die with prostate cancer than Whites. Stage at diagnosis is a key prognostic factor for prostate cancer survival, with African-Americans generally diagnosed at a more advanced stage. To identify factors that explain the race-stage disparity in prostate cancer, we conducted a population-based case-case study of 251 African-American (46%) and White (54%) prostate cancer cases diagnosed in Connecticut between January 1987 and October 1990. Multivariate logistic regression was used to identify potential explanatory factors, including clinical, sociodemographic, medical care, insurance, digital rectal examination screening history, and lifestyle factors. Cox proportional hazards models assessed the impact of study variables on race differences in long-term survival. Modifiable factors such as screening practice and sociodemographic factors accounted for >60% of the race difference in prostate cancer stage at diagnosis. Histologic grade (Gleason score) accounted for comparatively less. Survival analyses confirmed the importance of tumor characteristics, education, and insurance in explaining observed race differences in survival. Although cases were identified before the widespread use of prostate-specific antigen (PSA) screening, the results should also be relevant to countries that have large underserved populations and/or disparities in access to medical care and cancer screening.