Publications

Objects in scenes follow a hierarchical organization, with "scenes" at the top level, followed by "phrases", clusters of objects that share spatial and functional proximity. Within these phrases, "anchor" objects help predict the identity and location of smaller, dependent "local" objects. Previous research has shown that this hierarchy is reflected in the mental representations of objects in adults. The current study examined whether children's object representations already reflect this hierarchy. We implemented an odd-one-out task with 36 object images to collect pairwise similarity ratings from children ages 5 to 10 years. Two different groups of children received different similarity judgment instructions: One group received no explicit definition of similarity, but the other was told to base similarity on actions typically performed with the objects. We created a priori and data-driven scene hierarchy measures to evaluate how well they aligned with children's similarity judgments. Results showed that children's representations were clearly structured at the scene level, as indicated by strong effects in both hierarchy measures. In contrast, we found no reliable phrase-level effects and only a small data-driven object-type effect. Scene-level structure strengthened with age, whereas phrase- and object-type levels showed no reliable age-related change. Importantly, similarity patterns were highly comparable across both tasks, suggesting that children's object representations by default seem to be action based. These results suggest that children organize objects along the scene level of the hierarchy incorporating actions related to the objects in their representations, whereas finer-grained relations are more weakly represented and may be more difficult to detect reliably at this age.

Hue percepts vary more rapidly along some directions in color space (e.g., near yellow) than others (e.g., near green), with corresponding differences in the size or stimulus range of different hue categories. The basis for these differences is not known. We examined whether the asymmetries are present in early cortical color coding by comparing the strength of hue differences using visual evoked potentials (VEPs) recorded from the occipital cortex. Stimuli were spatial gratings with a fixed nominal contrast in the cone-opponent plane that varied sinusoidally in hue rather than saturation. The responses to different levels of hue separation were measured by the amplitude of the frequency-tagged signals and also in behavioral measurements employing a contrast matching task. For both, the same separation in hue angle resulted in stronger responses for angular differences centered on the yellow quadrant of the cone-opponent space. Responses were also larger for the yellow than blue quadrant, ruling out a general sensitivity loss to the blue-yellow axis as the basis for the differences. The response differences paralleled the asymmetries in the rates of change in color appearance based on analyses of previous measures of hue scaling functions. The presence of these asymmetries in the VEP responses suggests that they arise relatively early in the cortical sensory representation of color rather than emerging late as a product of inference or color category learning.

How is the perceptual representation of a spatially extended object translated into a discrete saccade vector? A wealth of evidence suggests that the object center of area (COA) is computed as a default index. However, saccades are also sensitive to the location of task-relevant information, which does not always appear at the COA. In addition, task-relevant object regions often correspond to discrete object parts. Here, we manipulated part-structure cues and participant goals to examine their potential interaction in controlling within-object landing position. In Experiment 1, participants executed saccades to spatially extended objects in a visual search task. Within-object landing position was systematically influenced by both factors: (1) a bias toward locations known to contain task-relevant information, and (2) a bias toward regions of part segmentation. A rapid orienting task to a single, abruptly appearing object (Experiment 2) showed only the latter bias, suggesting that unlike the strategic bias, the segmentation bias was driven primarily by physical stimulus properties. Finally, the two biases combined, such that the largest effect of strategy was observed when the relevant location coincided with a discrete object part. Together, the results indicate that saccade target selection was controlled by the combined effect of goal-directed processes, segmentation, and a default bias toward the COA.

PURPOSE: Laboratory rodents are commonly euthanized by exposure to gradually increasing concentrations of carbon dioxide (CO2). CO2 exposure induces respiratory acidosis, reduces dopamine levels, and causes hypoxia in central nervous system tissues, potentially affecting their physiology. These effects may be critical for brain and retinal tissues, yet the impact of CO2 euthanasia remains largely unclear.

METHODS: Using dark-adapted transretinal electroretinography (tERG), we tested the hypothesis that terminal CO2 overdose alters mouse retinal physiology. Two CO2 displacement rates were used, 30% and 60% of the chamber volume/min, with cervical dislocation as a reference method.

RESULTS: Neither slow nor fast CO2 overdose euthanasia affects rod photoreceptor and ON-bipolar cell flash responses. Activation and deactivation of rod phototransduction were not affected by CO2 overdose. However, both flow rates of CO2 exposure led to decreased cone photoreceptor response amplitudes and increased power spectral density integrals of oscillatory potentials (OPs). Moreover, Müller glia flash response amplitudes were reduced, and OPs were faster and more synchronized with the slower CO2 displacement rate compared to the two other euthanasia methods. In the mammalian retina, carbonic anhydrase is expressed in Müller glia, retinal pigment epithelium, most cone photoreceptors and a subset of amacrine cells.

CONCLUSIONS: Our findings indicate that CO2 euthanasia can generally be considered a safe termination method for retinal research, but caution should be taken when studying the physiology of carbonic anhydrase-expressing cells.

PURPOSE: This study aimed to explore the relationship between the ratio of red cell distribution width to albumin (RAR) and cataract risk.

METHODS: We analyzed 13,031 participants from the National Health and Nutrition Examination Survey 1999-2008. The RAR was evaluated as a composite marker of systemic inflammation and nutritional status. Multivariable logistic regression and receiver operating characteristic analysis were used to assess the association and discriminative ability of the RAR compared with other inflammatory markers.

RESULTS: The findings indicated a positive link between higher RAR levels and the risk of cataracts, with a nonlinear relationship exhibiting an inverted U shape. Individuals in the higher quartiles of the RAR were observed to have a significantly greater risk of cataracts compared with those in the lower quartiles. The area under the curve for the RAR in predicting cataracts was determined to be 0.601, suggesting a greater predictive capability compared with other inflammatory markers, including the neutrophil-to-lymphocyte ratio and the Systemic Immune Inflammation Index.

CONCLUSIONS: A higher RAR is significantly associated with moderate-to-severe cataracts. An RAR threshold of >3.025 may serve as a practical metric for identifying high-risk individuals, particularly among those aged ≥50 years.

TRANSLATIONAL RELEVANCE: As a routine and cost-effective marker of inflammation and nutrition, the red cell distribution width-to-albumin ratio offers a practical tool to support cataract risk stratification and early identification in primary care settings.

OBJECTIVE: To assess trends in educational inequalities in gastric cancer (GC) incidence and mortality in Quito, Ecuador, from 1996 to 2015.

METHODS: Using data available from the population-based cancer registry of Quito, age-specific standardised incidence and mortality rates for GC were calculated by educational level and sex. Using robust Poisson regression models, rate ratios, relative index of inequality (RII) and the slope index of inequality (SII) in incidence and mortality by educational level were estimated. Joinpoint regression analysis was performed to estimate the average annual percentage change.

RESULTS: The risk of developing GC among the less educated was substantially greater than among the most educated in both men and women, being around double the risk in relative terms (RIIwomen =2.1; 95% CI: 1.9, 2.3; RIImen = 1.7; 95% CI: 1.5, 1.8) and representing 14-15 cases per 100,000 person-years more cases in the lowest versus the highest educational levels (SIIwomen = 14.2; 95% CI: 12.2, 16.2; SIImen = 14.5; 95% CI: 12.0, 17.1). The differences were slightly greater for mortality.

DISCUSSION: Strong educational inequalities in GC incidence and mortality rates in Quito were observed. Efforts to target specific strategies among individuals with low education may help to ameliorate socioeconomic disparities in cancer incidence and mortality.

INTRODUCTION AND BACKGROUND: Febrile Neutropenia is one of the leading causes of treatment-related mortality in children with malignancies. Door-to-needle-time (DTNT), defined as the time between arrival at hospital and antibiotic administration, of <60 minutes is considered standard of care in managing this oncological emergency.

OBJECTIVES: In this quality improvement (QI) study, we aim to determine the proportion of children with febrile neutropenia (FN) receiving timely antibiotics in the Paediatric Emergency unit and improve this by 50% over 6 months using the Plan-Do-Study-Act framework. Secondary objectives included identifying factors associated with delays in achieving optimal DTNT and the impact of these delays on clinical outcomes.

METHODS: Baseline data of children less than 18 years of age on cancer chemotherapy presenting with neutropenic fever between January 2022 and June 2023 were collected ambispectively. A fishbone root cause analysis was performed. Interventions were planned and prioritised using a prioritisation matrix. QI measures were initiated subsequently in the form of the development and implementation of a validated clinical care pathway that described the triaging, clinical assessment, laboratory investigations, antibiotic dosing and patient disposition. Additionally, mannequin-assisted, followed by bedside training on chemoport handling, was performed. Post-intervention data, including the 6-months sustenance phase, were collected, and outcomes were analysed.

RESULTS: In the baseline, intervention and sustenance periods, 129, 80 and 47 episodes of FN, respectively, were documented. Median DTNT reduced by 50% from a baseline of 80 minutes interquartile range (IQR 65-105) to 40 minutes (IQR 30-40) post-intervention (p < 0.001). The proportion of children with optimal DTNT increased from 22% to 92.5% (p < 0.001). DTNT > 60 minutes was significantly associated with intensive care admissions. Root-Cause-Analysis revealed difficult peripheral venous access, lack of awareness and implementation challenges as the most important causes for delays in antibiotic administration.

CONCLUSIONS: The median DTNT was significantly delayed in patients with FN. Inadequate knowledge and skills training, delays in vascular access and lack of implementation of standard protocols were identified as the key factors responsible for delays in antibiotic administration. QI strategies aimed at improving awareness and skill with rigorous training programs as well as clinical pathway implementation, significantly improved the time to antibiotic administration.

Acute lymphoblastic leukaemia (ALL) can mimic diverse musculoskeletal conditions, often resulting in diagnostic delays. Genetic predisposition to various cancer syndromes further complicates the clinical picture, influencing disease presentation and treatment response. We report an adolescent boy who presented with a 2-month history of episodic fever, persistent low back pain and non-migratory joint pain, with a history of growth failure, developmental delay and seizures since childhood. There was a history of malignancy in multiple family members. The clinical examination revealed no features suggestive of systemic involvement. The joint examination revealed swelling around the knee joints. Initial work-up for chronic infections and autoimmune diseases was negative. Magnetic resonance imaging spine findings of multiple T2 hyperintense lesions warranted a bone marrow examination, which confirmed the diagnosis of Ph+ B- ALL. Molecular analysis revealed a pathogenic heterozygous missense variant in the TP53 gene, leading to the diagnosis of Li-Fraumeni syndrome. This case highlights the importance of recognizing musculoskeletal symptoms as a potential presentation of ALL. Early consideration of leukaemia in the differential diagnosis can prevent delays in treatment, ultimately improving outcomes.

BACKGROUND: Social networks (SNs) are increasingly shaping the landscape of cancer care by providing online platforms for information exchange, emotional support and patient engagement. However, the nuanced experiences of patients using these platforms, along with the associated risks and expectations, remain underexplored. This qualitative study aimed to investigate cancer patients' perspectives on the role of SNs throughout their care journey.

METHODS: A phenomenological design was employed in 2024, involving 20 cancer patients who were active users of SNs. Participants were purposively selected from hospitals affiliated with Urmia University of Medical Sciences, Iran. Data were collected through semi-structured interviews focusing on three main areas: perceived opportunities, challenges and expectations. Thematic analysis was conducted following Braun and Clarke's six-phase framework.

RESULTS: Findings are presented within three main categories derived from the interview guide: opportunities, challenges and expectations. Thematic analysis revealed several key subthemes under each category. Opportunities included enhanced cancer awareness, improved communication with healthcare providers, emotional support and self-care promotion. Challenges encompassed misinformation, privacy breaches, emotional distress, social isolation and commercial exploitation. Expectations included greater provider engagement as well as improved access to reliable treatment information and social support.

CONCLUSION: Findings highlight that while SNs offer meaningful benefits in cancer care, they also pose substantial risks. To maximise their utility and minimise harm, these platforms must prioritise content accuracy, user privacy and clinical collaboration. To be effective in health contexts, SNs should specifically address health-related issues.

OBJECTIVE: To assess whether the number of lymph nodes (LN) in breast cancer (BC) patients undergoing axillary dissection (AD) after neoadjuvant chemotherapy affects disease-free survival (DFS) and overall survival (OS).

METHODS: Descriptive, retrospective, longitudinal cut-off study (2011-2020).

RESULTS: 391 patients, 176 patients in the <10 LNs group and 215 ≥10 dissected LGs. The mean number of dissected nodes was 6.2 and 13.8 in the < or ≥ 10 LN groups, respectively. The <10 LN group had a higher proportion of stage IIIB (p = 0.012) and ypN0 (p = 0.001) patients and higher frequency in the phenotypes: luminal A 23.5%, TN 24.1% and HER 2 18.7% when compared with patients with ≥10 LN. Patients with ≥10 LN retrieved had a higher mean OS compared to the group of patients <10 LN with no statistical association (p = 0.184) (hazard ratio = 1.91 95% CI: 0.73-4.98) and a survival probability at 120 months (both groups) of 96.2%. There was also no statistical difference in the DFS when comparing the two groups of patients, indicating that the number of nodes removed is not associated with a differential risk of relapse, with a survival probability at 120 months of 63.3%.

CONCLUSION: The results of the study indicate that the number of nodes removed during AD does not affect survival (OS and EFS) in patients with neoadjuvant (ypN0/ypN+) BC. Axillary staging remains a key factor in the management of BC; therefore, an individualised approach considering the response to triple negative breast cancer and tumour burden in therapeutic decision making is recommended.