Exploring the Genetic Diversity of Epstein-Barr Virus among Patients with Gastric Cancer in Southern Chile.

The Epstein-Barr virus (EBV) has been associated with gastric cancer (GC), one of the deadliest malignancies in Chile and the world. Little is known about Chilean EBV strains. This study aims to investigate the frequency and genetic diversity of EBV in GC in patients in southern Chile. To evaluate the prevalence of EBV in GC patients from the Chilean population, we studied 54 GC samples using the gold standard detection method of EBV-encoded small RNA (EBER). The EBV-positive samples were subjected to amplification and sequencing of the Epstein-Barr virus nuclear protein 3A (EBNA3A) gene to evaluate the genetic diversity of EBV strains circulating in southern Chile. In total, 22.2% of the GC samples were EBV-positive and significantly associated with diffuse-type histology (p = 0.003). Phylogenetic analyses identified EBV-1 and EBV-2 in the GC samples, showing genetic diversity among Chilean isolates. This work provides important information for an epidemiological follow-up of the different EBV subtypes that may cause GC in southern Chile.

Non-pharmaceutical interventions, vaccination, and the SARS-CoV-2 delta variant in England: a mathematical modelling study.

BACKGROUND: England's COVID-19 roadmap out of lockdown policy set out the timeline and conditions for the stepwise lifting of non-pharmaceutical interventions (NPIs) as vaccination roll-out continued, with step one starting on March 8, 2021. In this study, we assess the roadmap, the impact of the delta (B.1.617.2) variant of SARS-CoV-2, and potential future epidemic trajectories. METHODS: This mathematical modelling study was done to assess the UK Government's four-step process to easing lockdown restrictions in England, UK. We extended a previously described model of SARS-CoV-2 transmission to incorporate vaccination and multi-strain dynamics to explicitly capture the emergence of the delta variant. We calibrated the model to English surveillance data, including hospital admissions, hospital occupancy, seroprevalence data, and population-level PCR testing data using a Bayesian evidence synthesis framework, then modelled the potential trajectory of the epidemic for a range of different schedules for relaxing NPIs. We estimated the resulting number of daily infections and hospital admissions, and daily and cumulative deaths. Three scenarios spanning a range of optimistic to pessimistic vaccine effectiveness, waning natural immunity, and cross-protection from previous infections were investigated. We also considered three levels of mixing after the lifting of restrictions. FINDINGS: The roadmap policy was successful in offsetting the increased transmission resulting from lifting NPIs starting on March 8, 2021, with increasing population immunity through vaccination. However, because of the emergence of the delta variant, with an estimated transmission advantage of 76% (95% credible interval [95% CrI] 69-83) over alpha, fully lifting NPIs on June 21, 2021, as originally planned might have led to 3900 (95% CrI 1500-5700) peak daily hospital admissions under our central parameter scenario. Delaying until July 19, 2021, reduced peak hospital admissions by three fold to 1400 (95% CrI 700-1700) per day. There was substantial uncertainty in the epidemic trajectory, with particular sensitivity to the transmissibility of delta, level of mixing, and estimates of vaccine effectiveness. INTERPRETATION: Our findings show that the risk of a large wave of COVID-19 hospital admissions resulting from lifting NPIs can be substantially mitigated if the timing of NPI relaxation is carefully balanced against vaccination coverage. However, with the delta variant, it might not be possible to fully lift NPIs without a third wave of hospital admissions and deaths, even if vaccination coverage is high. Variants of concern, their transmissibility, vaccine uptake, and vaccine effectiveness must be carefully monitored as countries relax pandemic control measures. FUNDING: National Institute for Health Research, UK Medical Research Council, Wellcome Trust, and UK Foreign, Commonwealth and Development Office.

Can High Exposure Help to Close Gaps? The Influence of COVID-19 Preventive Messages on Behavioral Intentions by Educational Attainment in Chile.

The literature in the field of health communication has shown the existence of gaps between groups of different socioeconomic levels both in exposure to health campaign messages and in the influence these messages exert on individuals' health decisions. In this article, we examine the association between educational attainment and exposure to messages promoting COVID-19 preventive behaviors, namely, physical distancing, handwashing, and masks wearing in Chile. In addition, we model the association between exposure to these messages and the intentions to carry out the behaviors, as well as the differences attributable to educational attainment in the influence of exposure. A cross-sectional population survey combining online and telephone techniques was conducted among 3,592 adults in Chile. Regression analysis revealed that lower educational level and frequency of television use were positively associated with greater exposure to preventive messages. Exposure to preventive messages, in turn, was positively associated with intentions to maintain the three behaviors examined. Individuals in the lower educational attainment group had lower intentions to engage in two of the three behaviors, but those in these segments who were more exposed to preventive messages were as likely as their more educated counterparts to intend wearing masks and adhering to physical distance. The findings of this study underscore the importance of reaching the least educated segments with campaign messages in the context of public health crisis, since these messages can close gaps between the more and less educated group in their intentions to engage in preventive behaviors.

Clinical Characteristics and Predictors of Outcomes of Hospitalized Patients With Coronavirus Disease 2019 in a Multiethnic London National Health Service Trust: A Retrospective Cohort Study.

BACKGROUND: Emerging evidence suggests ethnic minorities are disproportionately affected by coronavirus disease 2019 (COVID-19). Detailed clinical analyses of multicultural hospitalized patient cohorts remain largely undescribed. METHODS: We performed regression, survival, and cumulative competing risk analyses to evaluate factors associated with mortality in patients admitted for COVID-19 in 3 large London hospitals between 25 February and 5 April, censored as of 1 May 2020. RESULTS: Of 614 patients (median age, 69 [interquartile range, 25] years) and 62% male), 381 (62%) were discharged alive, 178 (29%) died, and 55 (9%) remained hospitalized at censoring. Severe hypoxemia (adjusted odds ratio [aOR], 4.25 [95% confidence interval {CI}, 2.36-7.64]), leukocytosis (aOR, 2.35 [95% CI, 1.35-4.11]), thrombocytopenia (aOR [1.01, 95% CI, 1.00-1.01], increase per 109 decrease), severe renal impairment (aOR, 5.14 [95% CI, 2.65-9.97]), and low albumin (aOR, 1.06 [95% CI, 1.02-1.09], increase per gram decrease) were associated with death. Forty percent (n = 244) were from black, Asian, and other minority ethnic (BAME) groups, 38% (n = 235) were white, and ethnicity was unknown for 22% (n = 135). BAME patients were younger and had fewer comorbidities. Although the unadjusted odds of death did not differ by ethnicity, when adjusting for age, sex, and comorbidities, black patients were at higher odds of death compared to whites (aOR, 1.69 [95% CI, 1.00-2.86]). This association was stronger when further adjusting for admission severity (aOR, 1.85 [95% CI, 1.06-3.24]). CONCLUSIONS: BAME patients were overrepresented in our cohort; when accounting for demographic and clinical profile of admission, black patients were at increased odds of death. Further research is needed into biologic drivers of differences in COVID-19 outcomes by ethnicity.

Association between HIV infection and hypertension: a global systematic review and meta-analysis of cross-sectional studies.

BACKGROUND: Improved access to effective antiretroviral therapy has meant that people living with HIV (PLHIV) are surviving to older ages. However, PLHIV may be ageing differently to HIV-negative individuals, with dissimilar burdens of non-communicable diseases, such as hypertension. While some observational studies have reported a higher risk of prevalent hypertension among PLHIV compared to HIV-negative individuals, others have found a reduced burden. To clarify the relationship between HIV and hypertension, we identified observational studies and pooled their results to assess whether there is a difference in hypertension risk by HIV status. METHODS: We performed a global systematic review and meta-analysis of published cross-sectional studies that examined hypertension risk by HIV status among adults aged > 15 (PROSPERO: CRD42019151359). We searched MEDLINE, EMBASE, Global Health and Cochrane CENTRAL to August 23, 2020, and checked reference lists of included articles. Our main outcome was the risk ratio for prevalent hypertension in PLHIV compared to HIV-negative individuals. Summary estimates were pooled with a random effects model and meta-regression explored whether any difference was associated with study-level factors. RESULTS: Of 21,527 identified studies, 59 were eligible (11,101,581 participants). Crude global hypertension risk was lower among PLHIV than HIV-negative individuals (risk ratio 0.90, 95% CI 0.85-0.96), although heterogeneity between studies was high (I2 = 97%, p < 0.0001). The relationship varied by continent, with risk higher among PLHIV in North America (1.12, 1.02-1.23) and lower among PLHIV in Africa (0.75, 0.68-0.83) and Asia (0.77, 0.63-0.95). Meta-regression revealed strong evidence of a difference in risk ratios when comparing North American and European studies to African ones (North America 1.45, 1.21-1.74; Europe 1.20, 1.03-1.40). CONCLUSIONS: Our findings suggest that the relationship between HIV status and prevalent hypertension differs by region. The results highlight the need to tailor hypertension prevention and care to local contexts and underscore the importance of rapidly optimising integration of services for HIV and hypertension in the worst affected regions. The role of different risk factors for hypertension in driving context-specific trends remains unclear, so development of further cohorts of PLHIV and HIV-negative controls focused on this would also be valuable.

The J-IDEA Pandemic Planner: A Framework for Implementing Hospital Provision Interventions During the COVID-19 Pandemic.

BACKGROUND: Planning for extreme surges in demand for hospital care of patients requiring urgent life-saving treatment for coronavirus disease 2019 (COVID-19), while retaining capacity for other emergency conditions, is one of the most challenging tasks faced by health care providers and policymakers during the pandemic. Health systems must be well-prepared to cope with large and sudden changes in demand by implementing interventions to ensure adequate access to care. We developed the first planning tool for the COVID-19 pandemic to account for how hospital provision interventions (such as cancelling elective surgery, setting up field hospitals, or hiring retired staff) will affect the capacity of hospitals to provide life-saving care. METHODS: We conducted a review of interventions implemented or considered in 12 European countries in March to April 2020, an evaluation of their impact on capacity, and a review of key parameters in the care of COVID-19 patients. This information was used to develop a planner capable of estimating the impact of specific interventions on doctors, nurses, beds, and respiratory support equipment. We applied this to a scenario-based case study of 1 intervention, the set-up of field hospitals in England, under varying levels of COVID-19 patients. RESULTS: The Abdul Latif Jameel Institute for Disease and Emergency Analytics pandemic planner is a hospital planning tool that allows hospital administrators, policymakers, and other decision-makers to calculate the amount of capacity in terms of beds, staff, and crucial medical equipment obtained by implementing the interventions. Flexible assumptions on baseline capacity, the number of hospitalizations, staff-to-beds ratios, and staff absences due to COVID-19 make the planner adaptable to multiple settings. The results of the case study show that while field hospitals alleviate the burden on the number of beds available, this intervention is futile unless the deficit of critical care nurses is addressed first. DISCUSSION: The tool supports decision-makers in delivering a fast and effective response to the pandemic. The unique contribution of the planner is that it allows users to compare the impact of interventions that change some or all inputs.

The impact of the COVID-19 pandemic on patterns of attendance at emergency departments in two large London hospitals: an observational study.

BACKGROUND: Hospitals in England have undergone considerable change to address the surge in demand imposed by the COVID-19 pandemic. The impact of this on emergency department (ED) attendances is unknown, especially for non-COVID-19 related emergencies. METHODS: This analysis is an observational study of ED attendances at the Imperial College Healthcare NHS Trust (ICHNT). We calibrated auto-regressive integrated moving average time-series models of ED attendances using historic (2015-2019) data. Forecasted trends were compared to present year ICHNT data for the period between March 12, 2020 (when England implemented the first COVID-19 public health measure) and May 31, 2020. We compared ICHTN trends with publicly available regional and national data. Lastly, we compared hospital admissions made via the ED and in-hospital mortality at ICHNT during the present year to the historic 5-year average. RESULTS: ED attendances at ICHNT decreased by 35% during the period after the first lockdown was imposed on March 12, 2020 and before May 31, 2020, reflecting broader trends seen for ED attendances across all England regions, which fell by approximately 50% for the same time frame. For ICHNT, the decrease in attendances was mainly amongst those aged < 65 years and those arriving by their own means (e.g. personal or public transport) and not correlated with any of the spatial dependencies analysed such as increasing distance from postcode of residence to the hospital. Emergency admissions of patients without COVID-19 after March 12, 2020 fell by 48%; we did not observe a significant change to the crude mortality risk in patients without COVID-19 (RR 1.13, 95%CI 0.94-1.37, p = 0.19). CONCLUSIONS: Our study findings reflect broader trends seen across England and give an indication how emergency healthcare seeking has drastically changed. At ICHNT, we find that a larger proportion arrived by ambulance and that hospitalisation outcomes of patients without COVID-19 did not differ from previous years. The extent to which these findings relate to ED avoidance behaviours compared to having sought alternative emergency health services outside of hospital remains unknown. National analyses and strategies to streamline emergency services in England going forward are urgently needed.

Mapping the Current and Future Noncommunicable Disease Burden in Kenya by Human Immunodeficiency Virus Status: A Modeling Study.

BACKGROUND: The noncommunicable disease (NCD) burden in Kenya is not well characterized, despite estimates needed to identify future health priorities. We aimed to quantify current and future NCD burden in Kenya by human immunodeficiency virus (HIV) status. METHODS: Original systematic reviews and meta-analyses of prevalence/incidence of cardiovascular disease (CVD), chronic kidney disease, depression, diabetes, high total cholesterol, hypertension, human papillomavirus infection, and related precancerous stages in Kenya were carried out. An individual-based model was developed, simulating births, deaths, HIV disease and treatment, aforementioned NCDs, and cancers. The model was parameterized using systematic reviews and epidemiological national and regional surveillance data. NCD burden was quantified for 2018-2035 by HIV status among adults. RESULTS: Systematic reviews identified prevalence/incidence data for each NCD except ischemic heart disease. The model estimates that 51% of Kenyan adults currently suffer from ≥1 NCD, with a higher burden in people living with HIV (PLWH) compared to persons not living with HIV (62% vs 51%), driven by their higher age profile and partly by HIV-related risk for NCDs. Hypertension and high total cholesterol are the main NCD drivers (adult prevalence of 20.5% [5.3 million] and 9.0% [2.3 million]), with CVD and cancers the main causes of death. The burden is projected to increase by 2035 (56% in persons not living with HIV; 71% in PLWH), with population growth doubling the number of people needing services (15.4 million to 28.1 million) by 2035. CONCLUSIONS: NCD services will need to be expanded in Kenya. Guidelines in Kenya already support provision of these among both the general and populations living with HIV; however, coverage remains low.

Adapting hospital capacity to meet changing demands during the COVID-19 pandemic.

BACKGROUND: To calculate hospital surge capacity, achieved via hospital provision interventions implemented for the emergency treatment of coronavirus disease 2019 (COVID-19) and other patients through March to May 2020; to evaluate the conditions for admitting patients for elective surgery under varying admission levels of COVID-19 patients. METHODS: We analysed National Health Service (NHS) datasets and literature reviews to estimate hospital care capacity before the pandemic (pre-pandemic baseline) and to quantify the impact of interventions (cancellation of elective surgery, field hospitals, use of private hospitals, deployment of former medical staff and deployment of newly qualified medical staff) for treatment of adult COVID-19 patients, focusing on general and acute (G&A) and critical care (CC) beds, staff and ventilators. RESULTS: NHS England would not have had sufficient capacity to treat all COVID-19 and other patients in March and April 2020 without the hospital provision interventions, which alleviated significant shortfalls in CC nurses, CC and G&A beds and CC junior doctors. All elective surgery can be conducted at normal pre-pandemic levels provided the other interventions are sustained, but only if the daily number of COVID-19 patients occupying CC beds is not greater than 1550 in the whole of England. If the other interventions are not maintained, then elective surgery can only be conducted if the number of COVID-19 patients occupying CC beds is not greater than 320. However, there is greater national capacity to treat G&A patients: without interventions, it takes almost 10,000 G&A COVID-19 patients before any G&A elective patients would be unable to be accommodated. CONCLUSIONS: Unless COVID-19 hospitalisations drop to low levels, there is a continued need to enhance critical care capacity in England with field hospitals, use of private hospitals or deployment of former and newly qualified medical staff to allow some or all elective surgery to take place.

Low Spontaneous Breathing Effort during Extracorporeal Membrane Oxygenation in a Porcine Model of Severe Acute Respiratory Distress Syndrome.

BACKGROUND: A lung rest strategy is recommended during extracorporeal membrane oxygenation in severe acute respiratory distress syndrome (ARDS). However, spontaneous breathing modes are frequently used in this context. The impact of this approach may depend on the intensity of breathing efforts. The authors aimed to determine whether a low spontaneous breathing effort strategy increases lung injury, compared to a controlled near-apneic ventilation, in a porcine severe ARDS model assisted by extracorporeal membrane oxygenation. METHODS: Twelve female pigs were subjected to lung injury by repeated lavages, followed by 2-h injurious ventilation. Thereafter, animals were connected to venovenous extracorporeal membrane oxygenation and during the first 3 h, ventilated with near-apneic ventilation (positive end-expiratory pressure, 10 cm H2O; driving pressure, 10 cm H2O; respiratory rate, 5/min). Then, animals were allocated into (1) near-apneic ventilation, which continued with the previous ventilatory settings; and (2) spontaneous breathing: neuromuscular blockers were stopped, sweep gas flow was decreased until regaining spontaneous efforts, and ventilation was switched to pressure support mode (pressure support, 10 cm H2O; positive end-expiratory pressure, 10 cm H2O). In both groups, sweep gas flow was adjusted to keep Paco2 between 30 and 50 mmHg. Respiratory and hemodynamic as well as electric impedance tomography data were collected. After 24 h, animals were euthanized and lungs extracted for histologic tissue analysis. RESULTS: Compared to near-apneic group, the spontaneous breathing group exhibited a higher respiratory rate (52 ± 17 vs. 5 ± 0 breaths/min; mean difference, 47; 95% CI, 34 to 59; P < 0.001), but similar tidal volume (2.3 ± 0.8 vs. 2.8 ± 0.4 ml/kg; mean difference, 0.6; 95% CI, -0.4 to 1.4; P = 0.983). Extracorporeal membrane oxygenation settings and gas exchange were similar between groups. Dorsal ventilation was higher in the spontaneous breathing group. No differences were observed regarding histologic lung injury. CONCLUSIONS: In an animal model of severe ARDS supported with extracorporeal membrane oxygenation, spontaneous breathing characterized by low-intensity efforts, high respiratory rates, and very low tidal volumes did not result in increased lung injury compared to controlled near-apneic ventilation.

Frequency of Human papillomavirus in women attending cervical cancer screening program in Chile.

BACKGROUND: Human papillomavirus (HPV) is the etiological factor for cervical cancer and its precursor lesions. The characterization of HPV genotypes in preneoplastic lesions and cervical cancer could establishes the effectiveness of vaccination plan in Chilean population. The aim of this study was to determine HPV frequency in a group of women including in a cervical screening program in the public health care system in Chile. METHODS: We analyzed 985 cervical smears samples from women with different histological diagnosis, attending to public health care in Temuco-Chile between 2004 and 2012, to detect HPV genotypes, through PCR followed by reverse line blotting assay. RESULTS: HPV was found present in 80.8% (n = 796) of samples. Only a 5.6% of 985 samples were infected with a low-risk HPV, considering multiple infections. 10.5% (n = 8/76) of normal cervical epithelia, 83.5% (n = 208/249) and 87.6% (n = 557/636) of low and high grade squamous intraepithelial lesions, respectively, and 95.8% (n = 23/24) of squamous cervical carcinomas tested positive for HPV. HPV 16 was the most frequent genotype found (Overall 44.9%, n = 442/985; SCC: 62.5%, n = 15/24). A high variability of HPV types was also found in preneoplastic lesions, whereas there was a selection of genotypes in neoplasia. Also, there was a higher risk of infection with HPV 16 in women ≤26 years and 34-41 years old (p < 0.05), meanwhile infections with HPV 16 or HPV 18 have related with cancer development (p < 0.01). CONCLUSIONS: These data provide further information about the frequency of HPV genotypes in women with cervical lesions in Chile, and the introduction of new targeted vaccines against a wider spectrum of HPV is suggested.

Invasive micropapillary carcinoma of the breast overexpresses MUC4 and is associated with poor outcome to adjuvant trastuzumab in HER2-positive breast cancer.

BACKGROUND: Invasive micropapillary carcinoma of the breast (IMPC) is a histological tumor variant that occurs with low frequency characterized by an inside-out formation of tumor clusters with a pseudopapillary arrangement. IMPC is an aggressive tumor with poor clinical outcome. In addition, this histological subtype usually expresses human epidermal growth factor receptor 2 (HER2) which also correlates with a more aggressive tumor. In this work we studied the clinical significance of IMPC in HER2-positive breast cancer patients treated with adjuvant trastuzumab. We also analyzed mucin 4 (MUC4) expression as a novel biomarker to identify IMPC. METHODS: We retrospectively studied 86 HER2-positive breast cancer patients treated with trastuzumab and chemotherapy in the adjuvant setting. We explored the association of the IMPC component with clinicopathological parameters at diagnosis and its prognostic value. We compared MUC4 expression in IMPC with respect to other histological breast cancer subtypes by immunohistochemistry. RESULTS: IMPC, either as a pure entity or associated with invasive ductal carcinoma (IDC), was present in 18.6% of HER2-positive cases. It was positively correlated with estrogen receptor expression and tumor size and inversely correlated with patient's age. Disease-free survival was significantly lower in patients with IMPC (hazard ratio = 2.6; 95%, confidence interval 1.1-6.1, P = 0.0340). MUC4, a glycoprotein associated with metastasis, was strongly expressed in all IMPC cases tested. IMPC appeared as the histological breast cancer subtype with the highest MUC4 expression compared to IDC, lobular and mucinous carcinoma. CONCLUSION: In HER2-positive breast cancer, the presence of IMPC should be carefully examined. As it is often not informed, because it is relatively difficult to identify or altogether overlooked, we propose MUC4 expression as a useful biomarker to highlight IMPC presence. Patients with MUC4-positive tumors with IMPC component should be more frequently monitored and/or receive additional therapies.

Resistance to Bean common mosaic necrosis virus Conferred by the bc-1 Gene Affects Systemic Spread of the Virus in Common Bean.

Bean common mosaic necrosis virus (BCMNV) isolates belong to two pathogroups (PG), PG-III and PG-VI, which are distinguished in common bean due to the inability of the PG-III isolates of BCMNV to overcome the two recessive resistance alleles bc-1 and bc-12. The biological and molecular basis of this distinction between PG-III and PG-VI isolates of BCMNV is not known. Here, three isolates of BCMNV were typed biologically on a set of 12 bean differentials and molecularly through whole-genome sequencing. Two isolates (1755b and TN1a) were assigned to PG-VI and one isolate (NL8-CA) was assigned to PG-III. Isolate NL8-CA (PG-III) induced only local necrosis on inoculated leaves in 'Top Crop' and 'Jubila' bean harboring the I gene and the bc-1 allele, whereas isolates TN1, TN1a, and 1755b (all PG-VI) induced rapid whole-plant necrosis (WPN) in Top Crop 7 to 14 days postinoculation, and severe systemic necrosis but not WPN in Jubila 3 to 5 weeks postinoculation. In 'Redland Greenleaf C' expressing bc-1 and 'Redland Greenleaf B' expressing bc-12 alleles, isolate NL8-CA was able to systemically infect only a small proportion of upper uninoculated leaves (less than 13 and 3%, respectively). The whole genomes of isolates 1755b, TN1a, and NL8-CA were sequenced and sequence analysis revealed that, despite the overall high nucleotide sequence identity between PG-III and PG-VI isolates (approximately 96%), two areas of the BCMNV genome in the P1/HC-Pro and HC-Pro/P3 cistrons appeared to be more divergent between these two pathotypes of BCMNV. The data suggest that the phenotypic differences among PG-III and PG-VI isolates of BCMNV in common bean cultivars from host resistance groups 2, 3, and 9 carrying bc-1 alleles were related to the impaired systemic movement of the PG-III isolates to the upper, uninoculated leaves, and also suggest a role of the recessive bc-1 gene in interfering with systemic spread of BCMNV.

Aerobic palladium-catalyzed dioxygenation of alkenes enabled by catalytic nitrite.

Catalytic nitrite was found to enable carbon-oxygen bond-forming reductive elimination from unstable alkyl palladium intermediates, providing dioxygenated products from alkenes. A variety of functional groups were tolerated, and high yields (up to 94 %) were observed with many substrates, also for a multigram-scale reaction. Nitrogen dioxide, which could form from nitrite under the reaction conditions, was demonstrated to be a potential intermediate in the catalytic cycle. Furthermore, the reductive elimination event was probed with (18) O-labeling experiments, which demonstrated that both oxygen atoms in the difunctionalized products were derived from one molecule of acetic acid.

Arterial mechanical motion estimation based on a semi-rigid body deformation approach.

Arterial motion estimation in ultrasound (US) sequences is a hard task due to noise and discontinuities in the signal derived from US artifacts. Characterizing the mechanical properties of the artery is a promising novel imaging technique to diagnose various cardiovascular pathologies and a new way of obtaining relevant clinical information, such as determining the absence of dicrotic peak, estimating the Augmentation Index (AIx), the arterial pressure or the arterial stiffness. One of the advantages of using US imaging is the non-invasive nature of the technique unlike Intra Vascular Ultra Sound (IVUS) or angiography invasive techniques, plus the relative low cost of the US units. In this paper, we propose a semi rigid deformable method based on Soft Bodies dynamics realized by a hybrid motion approach based on cross-correlation and optical flow methods to quantify the elasticity of the artery. We evaluate and compare different techniques (for instance optical flow methods) on which our approach is based. The goal of this comparative study is to identify the best model to be used and the impact of the accuracy of these different stages in the proposed method. To this end, an exhaustive assessment has been conducted in order to decide which model is the most appropriate for registering the variation of the arterial diameter over time. Our experiments involved a total of 1620 evaluations within nine simulated sequences of 84 frames each and the estimation of four error metrics. We conclude that our proposed approach obtains approximately 2.5 times higher accuracy than conventional state-of-the-art techniques.

[Genotyping of human papillomavirus in women under 25 years old treated in the screening program for cervical cancer]. / Genotipificación del virus papiloma humano en mujeres bajo 25 años de edad participantes del Programa Nacional del Cáncer Cérvico-uterino en la Región de la Araucanía, Chile.

BACKGROUND: In Chile, cervical cancer (CC) is the second leading cause of death from malignancy in women. The main causal agent of cervical cancer is the human papillomavirus (HPV). This virus is the most common sexually transmitted infection among sexually active youth. An early onset of sexual life increases the chances of HPV infection; this may involve a possible early development of cervical intraepithelial neoplasia and CC, creating a major public health problem. OBJECTIVE: To present HPV frequency in women under the age of 25, treated in the CC screening program and their follow-up after histopathological diagnosis. METHODS: 173 cervical samples were genotyped by polymerase chain reaction and non-radioactive reverse hybridization (line blot). RESULTS: The overall frequency of HPV was 84.8%. HPV16 was the most prevalent. In 12.1% of women the cervical lesion persisted or progressed. 28.9% of women had irregular follow-up; in this group, 88% were HPV(+) and 52% had no record of Pap smear in the past 3 years. DISCUSSION: The results reaffirm the usefulness of complementing the Pap and HPV detection as a primary screening tool in sexually active women. They also suggest the possibility of extending the age coverage of the national screening program.

Reversal of the regiochemistry in the rhodium-catalyzed [4+3] cycloaddition between vinyldiazoacetates and dienes.

A regio-, diastereo-, and enantioselective [4+3] cycloaddition between vinylcarbenes and dienes has been achieved using the dirhodium tetracarboxylate catalyst [Rh2(S-BTPCP)4]. This methodology provides facile access to 1,4-cycloheptadienes that are regioisomers of those formed from the tandem cyclopropanation/Cope rearrangement reaction of vinylcarbenes with dienes.