Self-assembly of rod-coil-rod block copolymers in a coil-selective solvent: coarse-grained simulation results.

The solution self-assembly of amphiphilic polymers provides a versatile approach to design novel nanostructured materials. Multiblock polymers, particularly those composed of liquid crystalline and coil blocks, are of significant interest due to the potential display of nematic ordering in liquid crystalline domains, offering intriguing optical and mechanical properties. In this study, dissipative particle dynamics is used to investigate the solution self-assembly of rod-coil-rod copolymers in a coil-selective solvent. Extensive molecular simulations were conducted to elucidate the impact of polymer composition, concentration and flexibility on the self-assembly behavior. A quantitative analysis was performed to investigate how polymer conformations varied with changes in composition, concentration, and rigidity. Simulation results show that, at small rod compositions, rod-coil-rod polymers self-assemble into micelles at low concentrations, transitioning to network formation as concentration increases. An increase in rod composition leads to the formation of larger aggregates, resulting in cylindrical micelles and membranes. The results reported here also offer insights into the role of flexibility in shaping the self-assembly behavior of rod-coil-rod triblocks in selective solvents, thus, contributing to a comprehensive understanding of the factors governing the formation of diverse structures in the solution self-assembly of triblock copolymers.

Childhood acute lymphoblastic leukemia survival and spatial analysis of socio-environmental risks in Mexico.

Background: Acute lymphoblastic leukemia (ALL) etiology remains largely unknown; incidence patterns by age, sex, and geographical distribution suggest a potential environmental role. Aim: To identify ALL clusters from four contrasting urban areas of Mexico and to characterize the sources of environmental carcinogens. Methods: Hospital-based ALL cases (n = 443) diagnosed in children <19 years old from the Metropolitan Zones of Merida and San Luis Potosi, the State of Mexico, and Tijuana were analyzed (2015-2020). ALL cases were coded according to the International Classification of Diseases for Oncology. ALL clusters were identified by Kernel Density, and excess risk was estimated. Data of particulate matter ≤2.5 µm (PM2.5) concentrations measured by community-monitoring stations were analyzed. Geocoded datasets of benzene, polycyclic aromatic hydrocarbons, and PM2.5 sources were analyzed to characterize patterns of exposure in ALL clusters. Results: The survival rate for ALL ranged from 61.5% to 78.6%. Seven ALL clusters with excess risk (RR 1.4-2.3, p < 0.05) were identified. The carcinogen sources included artisanal brick kilns, gas stations, cement works, carpentry, paint, and chemical manufacturing establishments. PM2.5 levels ranged from 15 µg/m3 to 37 µg/m3 among study areas. Conclusion: ALL clusters were identified at the community level; the excess risk could be explained by small-scale carcinogen sources. The levels of PM2.5 in outdoor air ranged from 3 to 6 times above the World Health Organization (WHO) air quality guidelines. Healthcare providers must raise awareness of the increased risk of ALL in children living near sources of environmental carcinogens; cancer control and prevention strategies must be steered from a multi-sectoral and multi-action perspective to protect children's health.

Tratamiento quirúrgico del leiomiosarcoma de vena cava inferior

Introducción: La baja incidencia del leiomiosarcoma de la vena cava inferior dificulta tanto la estandarización del diagnóstico como el tratamiento. Objetivo: Presentar el manejo realizado en nuestro centro de un paciente que desarrolló un leiomiosarcoma de vena cava inferior, una patología de baja incidencia y que las posibilidades de realizar un rescate quirúrgico son muy bajas. Resultados: Se presenta el caso de un paciente de 54 años con una tumoración sólida en porción infrarrenal y yuxtarrenal de vena cava inferior de 71 × 76 × 117 mm compatible con leiomiosarcoma de vena cava, con infiltración de uréter derecho que ocasiona uropatía obstructiva derecha grado I-II sin alteración de la función renal, que fue resecada y reconstruida mediante prótesis sin complicaciones. Discusión: Se discute la fisiopatología, el diagnóstico y manejo en relación con el caso presentado. Conclusión: la baja incidencia de estos tumores dificulta tanto la estandarización del diagnóstico como del tratamiento, aunque la cirugía sigue siendo el tratamiento de elección.

Introduction: The low incidence of leiomyosarcoma of the inferior vena cava hinders both the standardization of diagnosis and treatment. Objective: To present the management carried out in our center of a patient who developed an inferior vena cava leiomyosarcoma, a low incidence pathology with uncertain surgical rescue. Results: 54-year-old patient with a solid tumor in the infrarenal and juxtarenal portions of the inferior vena cava of 71 × 76 × 117 mm compatible with leiomyosarcoma of the vena cava, with infiltration of the right ureter that causes right obstructive uropathy grade I-II without kidney function changes; tumour was resected and continuity reconstructed with a prosthesis without complications. Discussion: The pathophysiology, diagnosis and management are commented. Conclusion: the low incidence of these lesions makes it difficult to standardize both diagnosis and treatment, although surgery remains the treatment of choice.

Vinyl Sulfone-functionalized Acetalated Dextran Microparticles as a Subunit Broadly Acting Influenza Vaccine.

Influenza is a global health concern with millions of infections occurring yearly. Seasonal flu vaccines are one way to combat this virus; however, they are poorly protective against influenza as the virus is constantly mutating, particularly at the immunodominant hemagglutinin (HA) head group. A more broadly acting approach involves Computationally Optimized Broadly Reactive Antigen (COBRA). COBRA HA generates a broad immune response that is capable of protecting against mutating strains. Unfortunately, protein-based vaccines are often weekly immunogenic, so to help boost the immune response, we employed the use of acetalated dextran (Ace-DEX) microparticles (MPs) two ways: one to conjugate COBRA HA to the surface and a second to encapsulate cGAMP. To conjugate the COBRA HA to the surface of the Ace-DEX MPs, a poly(L-lactide)-polyethylene glycol co-polymer with a vinyl sulfone terminal group (PLLA-PEG-VS) was used. MPs encapsulating the STING agonist cGAMP were co-delivered with the antigen to form a broadly active influenza vaccine. This vaccine approach was evaluated in vivo with a prime-boost-boost vaccination schedule and illustrated generation of a humoral and cellular response that could protect against a lethal challenge of A/California/07/2009 in BALB/c mice.

Dynamics and phase behavior of two-dimensional size-asymmetric binary mixtures of core-softened colloids.

The self-assembly of binary colloidal mixtures provides a bottom-up approach to create novel functional materials. To elucidate the effect of composition, temperature, and pressure on the self-assembly behavior of size-asymmetric mixtures, we performed extensive dynamics simulations of a simple model of polymer-grafted colloids. We have used a core-softened interaction potential and extended it to represent attractive interactions between unlike colloids and repulsions between like colloids. Our study focused on size-asymmetric mixtures where the ratio between the sizes of the colloidal cores was fixed at σBσA=0.5. We have performed extensive simulations in the isothermal-isobaric and canonical (NVT) ensembles to elucidate the phase behavior and dynamics of mixtures with different stoichiometric ratios. Our simulation results uncovered a rich phase behavior, including the formation of hierarchical structures with many potential applications. For compositions where small colloids are the majority, sublattice melting occurs for a wide range of densities. Under these conditions, large colloids form a well-defined lattice, whereas small colloids can diffuse through the system. As the temperature is decreased, the small colloids localize, akin to a metal-insulator transition, with the small colloids playing a role similar to electrons. Our results are summarized in terms of phase diagrams.

Phase behavior of a two-dimensional core-softened system: new physical insights.

In this work, we report results of extensive computer simulations regarding the phase behavior of a core-softened system. By using structural and thermodynamic descriptors, as well as self-diffusion coefficients, we provide a comprehensive view of the rich phase behavior displayed by the particular instance of the model studied in here. Our calculations agree with previously published results focused on a smaller region in the temperature-density parameter space (Dudalov et al 2014 Soft Matter 10 4966). In this work, we explore a broader region in this parameter space, and uncover interesting fluid phases with low-symmetry local order, that were not reported by previous works. Solid phases were also found, and have been previously characterized in detail by (Kryuchkov et al 2018 Soft Matter 14 2152). Our results support previously reported findings, and provide new physical insights regarding the emergence of order as disordered phases transform into solids by providing radial distribution function maps and specific heat data. Our results are summarized in terms of a phase diagram.

Gestational trophoblastic neoplasia in American Indians.

OBJECTIVE: To analyze gestational trophoblastic neoplasia (GTN) trends among American Indians (AI) using population-based data. STUDY DESIGN: GTN incidence, by race and age, was calculated using data collected by the New Mexico Tumor Registry over 29 years (1973-2001). Live birth, pregnancy and women at risk were tabulated using data derived from the state's vital record annual reports and from the registry. Statistical methods included trends analysis and Poisson regression. There is no national registry in the United States for all GTN. Therefore, the Surveillance, Epidemiology and End Results (SEER) database was used to identify choriocarcinoma cases in American Indians between 1973 and 1999. RESULTS: Within New Mexico, 1,082 cases of GTN were identified among 752,374 live births and 904,831 pregnancies, with ratios of 1:695 and 1:836, respectively, affecting 234 AI, 355 non-Hispanic whites (NHW), 463 Hispanic whites (HW) and 30 other nonwhites. Ratios per live births (pregnancy), respectively, were significantly higher in AI (AI 1:439 [1:487], NHW 1:739 [1:949], HW 1:783 [1:903]), as was age-adjusted incidence per 100,000 woman-years (AI 10.62, NHW 3.53, HW 5.15; all P<.0001). Using Poisson models with live birth and woman-year denominators, AI were found to be at increased risk for all GTN histologic subsets (complete, partial and invasive hydatidiform mole and choriocarcinoma). Of 524 total gestational choriocarcinoma cases identified within SEER, 8 (1.8%) affected American Indians; of them, 7 were from New Mexico. CONCLUSION: In New Mexico, AI continue to be at higher risk of GTN than are other groups. Given the rarity of choriocarcinoma within SEER, especially among AI, the New Mexico dataset provides the best available estimate of trends in U.S. AI GTN risk.

Trends in gestational choriocarcinoma: a 27-year perspective.

OBJECTIVE: To evaluate trends in incidence and survival rates for gestational choriocarcinoma with the use of population-based data. METHODS: Overall and 5-year average age-adjusted incidence rates were computed with the Surveillance, Epidemiology, and End Results program public-use database. Differences by age at diagnosis, race, stage, registry, and over calendar time were compared by Poisson regression, and survival censored for deaths other than choriocarcinoma by log-rank tests and Cox's proportional hazard ratios. RESULTS: Between 1973 and 1999, 450 cases were recorded. The annualized age-adjusted incidence rate for choriocarcinoma was 0.133 per 100,000 woman-years and decreased by 49.7% (2.8% per year). By race (whites, blacks, and others), incidence rates declined by 62.3%, 27.2%, and 54.3%, respectively. In the Poisson model evaluating incidence rates, age, race, registry, and stage were significant main effects. Compared with whites, the relative risk was higher for blacks (2.14, 95% confidence interval [CI] 1.60, 2.86) and others (2.30, 95% CI 1.67, 3.18). Rates were highest in Utah and lowest in Iowa. By age at diagnosis, rates were higher in 20-39-year-olds. The 5-year relative survival rate was 89.5%. Censored survival was significantly lower among blacks (whites 92.4%, blacks 84.9%, others 87.1%, P = .045), for advanced disease (localized 94.5%, regional 92.9%, distant 87.1%, P = .02), and with increasing age at diagnosis (P = .017). Age and calendar time significantly influenced censored survival independent of stage and registry. CONCLUSION: Gestational choriocarcinoma incidence rates have declined and survivals have improved, but blacks continue to have higher incidence and lower survival rates.

Is there a difference in survival for IA1 and IA2 adenocarcinoma of the uterine cervix?

OBJECTIVE: The goal of this study was to determine if International Federation of Obstetrics and Gynecology (FIGO) subdivision into IA1 versus IA2 is predictive of survival differences for early invasive adenocarcinoma. METHODS: The Surveillance, Epidemiology, and End-Results (SEER) Public-Use Database was used to identify all cases of IA1 and IA2 adenocarcinoma diagnosed between 1983 and 1997. A systematic literature search (MEDLINE 1966-2000) was used to identify all previously published cases. Stage, depth of invasion, node status, therapy, and survival were analyzed using Fisher's exact and log-rank tests. RESULTS: In SEER, 560 cases were identified: 200 IA1, 286 IA2, and 74 localized. Simple hysterectomy was performed in 272 (48.6%) and radical hysterectomy in 210 (37.5%). Positive lymph nodes were found in 3 of 197 (1.5%) who underwent lymphadenectomy, 2 of whom died. The censored survival by stage (mean follow-up 51.6 months) was not significantly different (P = 0.77) for IA1 versus IA2 (98.5% vs 98.6%). Combining these data with all other published series of early cervical adenocarcinoma, 1170 cases were identified, including 585 IA1, 358 IA2, and 227 "others," with less defined early disease. Of 531 (45.4%) who underwent lymphadenectomy, 15 (1.28%) had one or more positive nodes; of these, 11 (73.3%) recurred or died. For IA1 versus IA2 disease, there were no significant differences in the frequency of positive lymph nodes, recurrence, or death. However, "others," those with less well-defined lesions, or larger than IA2, were at increased risk. CONCLUSION: Early invasive adenocarcinoma (IA1 and IA2) has an excellent prognosis and conservative surgery may be appropriate. Since current FIGO staging definitions do not distinguish high- from low-risk disease, individualization of therapy based on pathology review, risk assessment, and patient preference is recommended.

Evidence of an association between human papillomavirus and impaired chemotherapy-induced apoptosis in cervical cancer cells.

OBJECTIVES: The aim of this study was to determine cervical cancer cell sensitivity to chemotherapy-induced apoptosis based on human papillomavirus (HPV) status. METHODS: CaSki (HPV-positive) and C33A (HPV-negative) cells were treated with camptothecin or cisplatin. Cellular viability was determined by trypan blue exclusion. Apoptotic indexes were determined by flow cytometric analysis of annexin V labeling and morphological changes. Mitochondrial release of cytochrome c was determined by immunofluorescence using confocal microscopy. Caspase 3 activation and bax expression were assessed by immunoblotting. RESULTS: CaSki cells displayed chemoresistance to both camptothecin and cisplatin. Low response to apoptogenic stimuli was evidenced by a marginal increase in the apoptotic cell fraction after camptothecin treatment (22.9 +/- 2.56%) compared with control (17.8 +/- 1.95%). Cisplatin (14.8 +/- 1.01%) caused a slight decrease in apoptosis. Mitochondrial release of cytochrome c and cleavage of caspase 3 could not be demonstrated in CaSki cells after treatment. Despite p53 mutation, C33A cells were sensitive to the antiproliferative effects of camptothecin and cisplatin. Mean apoptotic events were 17.5 +/- 0.33 for control, 42 +/- 1.76 for cisplatin, and 38.1 +/- 0.75 for camptothecin. An intact cytochrome c pathway was demonstrated in C33A cells leading to cleavage of caspase 3 after camptothecin treatment. The constitutive bax expression demonstrated in both cell lines displayed no change after camptothecin treatment. CONCLUSION: HPV-positive cervical cancer cells have an inherent resistance to chemotherapy-induced apoptosis. HPV-dependant inactivation of apoptotic regulators such as p53 and blockage of downstream events such as cytochrome c release and caspase 3 activation might be elemental to this cellular survival advantage provided by high-risk oncogenic papillomavirus.