Temporal progression of pancreatic cancer computed tomography findings until diagnosis: A large-scale multicenter study.

BACKGROUND: Focal parenchymal atrophy and main pancreatic duct (MPD) dilatation have been identified as early signs of pancreatic ductal adenocarcinoma. However, limited evidence exists regarding their temporal progression due to previous study limitations with restricted case numbers. OBJECTIVE: To ascertain a more precise frequency assessment of suspicious pancreatic ductal adenocarcinoma findings as well as delineate the temporal progression of them. METHODS: A multicenter retrospective study was conducted on patients diagnosed with pancreatic ductal adenocarcinoma between 2015 and 2021. We included patients who had undergone at least one computed tomography (CT) scan ≥6 months before diagnosing pancreatic ductal adenocarcinoma. The temporal progression of suspicious pancreatic ductal adenocarcinoma findings on CT was investigated. RESULTS: Out of 1832 patients diagnosed with pancreatic ductal adenocarcinoma, 320 had a previous CT before their diagnosis. Suspicious pancreatic ductal adenocarcinoma findings were detected in 153 cases (47.8%), with focal parenchymal atrophy (26.6%) being the most common followed by MPD dilatation (11.3%). Focal parenchymal atrophy was the earliest detectable sign among all suspicious findings and became visible on average 2.7 years before diagnosis, and the next most common, MPD dilatation, 1.1 years before diagnosis. Other findings, such as retention cysts, were less frequent and appeared around 1 year before diagnosis. Focal parenchymal atrophy followed by MPD dilatation was observed in 10 patients but not in reverse order. Focal parenchymal atrophy was more frequently detected in the pancreatic body/tail. No significant relationship was found between the pathological pancreatic ductal adenocarcinoma differentiation or tumor stage and the time course of the CT findings. All cases of focal parenchymal atrophy progressed just prior to diagnosis, and the atrophic area was occupied by tumor at diagnosis. Main pancreatic duct dilatation continued to progress until diagnosis. CONCLUSION: This large-scale study revealed that the temporal progression of focal parenchymal atrophy is the earliest detectable sign indicating pancreatic ductal adenocarcinoma. These results provide crucial insights for early pancreatic ductal adenocarcinoma detection.

Temporal Sequence of Post-Mortem Autolysis in the Mouse Retina.

In order to better differentiate ante-mortem lesions from post-mortem retinal autolysis, the temporal sequence of post-mortem changes was studied in a well-controlled mouse model. Mice were of the same strain, age and sex, and were held at a constant ambient temperature. Eyes were collected at various times up to 72 h after death and immersion-fixed in either Davidson's fixative or 10% neutral buffered formalin, paraffin-embedded and sections cut and stained with haematoxylin and eosin. The most prominent, and early, autolytic change was retinal detachment, and subsequent folding, which occurred immediately after death in formalin-fixed eyes, but not until 2 h post mortem with Davidson's fixative. Retinal separation was complete at 16 h, or almost complete by 2 h, in formalin, but in Davidson's fixative, was only partial and segmental, the latter not becoming total until much later. Retinal detachment was attended by progressively more severe disruption and dissolution of photoreceptors and, particularly in Davidson's-fixed retinas, the rod outer segment often showed marked homogenization from 30 min to 4 h after death. The other major early change was nuclear pyknosis in the inner nuclear layer. Ganglion cells initially had cytoplasmic swelling, followed by shrinkage and basophilia (at 4 h with formalin and 16 h with Davidson's), with nuclear pyknosis becoming increasingly common over time. While the three retinal neuronal layers eventually became more attenuated and depleted of cells, the thickness of these layers was augmented by severe swelling. These findings show that the post-mortem interval at which histological interpretation of retinal changes becomes potentially compromised is dependent on the duration of this interval and the fixative used.

Indications of Depressive Symptoms During the COVID-19 Pandemic in Germany: Comparison of National Survey and Twitter Data.

BACKGROUND: The current COVID-19 pandemic is associated with extensive individual and societal challenges, including challenges to both physical and mental health. To date, the development of mental health problems such as depressive symptoms accompanying population-based federal distancing measures is largely unknown, and opportunities for rapid, effective, and valid monitoring are currently a relevant matter of investigation. OBJECTIVE: In this study, we aim to investigate, first, the temporal progression of depressive symptoms during the COVID-19 pandemic and, second, the consistency of the results from tweets and survey-based self-reports of depressive symptoms within the same time period. METHODS: Based on a cross-sectional population survey of 9011 German adolescents and adults (n=4659, 51.7% female; age groups from 15 to 50 years and older) and a sample of 88,900 tweets (n=74,587, 83.9% female; age groups from 10 to 50 years and older), we investigated five depressive symptoms (eg, depressed mood and energy loss) using items from the Patient Health Questionnaire (PHQ-8) before, during, and after relaxation of the first German social contact ban from January to July 2020. RESULTS: On average, feelings of worthlessness were the least frequently reported symptom (survey: n=1011, 13.9%; Twitter: n=5103, 5.7%) and fatigue or loss of energy was the most frequently reported depressive symptom (survey: n=4472, 51.6%; Twitter: n=31,005, 34.9%) among both the survey and Twitter respondents. Young adult women and people living in federal districts with high COVID-19 infection rates were at an increased risk for depressive symptoms. The comparison of the survey and Twitter data before and after the first contact ban showed that German adolescents and adults had a significant decrease in feelings of fatigue and energy loss over time. The temporal progression of depressive symptoms showed high correspondence between both data sources (ρ=0.76-0.93; P<.001), except for diminished interest and depressed mood, which showed a steady increase even after the relaxation of the contact ban among the Twitter respondents but not among the survey respondents. CONCLUSIONS: Overall, the results indicate relatively small differences in depressive symptoms associated with social distancing measures during the COVID-19 pandemic and highlight the need to differentiate between positive (eg, energy level) and negative (eg, depressed mood) associations and variations over time. The results also underscore previous suggestions of Twitter data's potential to help identify hot spots of declining and improving public mental health and thereby help provide early intervention measures, especially for young and middle-aged adults. Further efforts are needed to investigate the long-term consequences of recurring lockdown phases and to address the limitations of social media data such as Twitter data to establish real-time public mental surveillance approaches.

Effects of West Nile virus dose and extrinsic incubation temperature on temporal progression of vector competence in Culex pipiens quinquefasciatus.

Culex pipiens quinquefasciatus were fed blood containing either 7.0 +/- 0.1 logs plaque-forming units (pfu)/ml (high dose) or 5.9 +/- 0.1 logs pfu/ml (low dose) of West Nile virus and held at extrinsic incubation temperatures (EIT) of 28 degrees C or 25 degrees C. Approximately 20 mosquitoes per dose were collected after incubation periods (IP) of 4, 6, 8, and 12 days postinfection (dpi). Infection rates were influenced by EIT and virus dose but not by IP. Body titer was significantly higher for mosquitoes fed the high dose and held at 28 degrees C at the later IPs (6, 8, and 12 dpi). However, leg titer was significantly higher for mosquitoes at the later IPs but did not differ between EITs or doses. Because infection rates varied with EIT and dose, there is likely a midgut infection barrier influenced by these factors that is not influenced by IP. Dissemination rates were influenced by all 3 factors consistent with the presence of a midgut escape barrier. Dissemination rate, body titer, and leg titer were dependent on IP, indicating the need to investigate multiple time points in vector competence studies to elucidate critical events in infection and dissemination.