Relating Pupil Diameter and Blinking to Cortical Activity and Hemodynamics across Arousal States.

Arousal state affects neural activity and vascular dynamics in the cortex, with sleep associated with large changes in the local field potential and increases in cortical blood flow. We investigated the relationship between pupil diameter and blink rate with neural activity and blood volume in the somatosensory cortex in male and female unanesthetized, head-fixed mice. We monitored these variables while the mice were awake, during periods of rapid eye movement (REM), and non-rapid eye movement (NREM) sleep. Pupil diameter was smaller during sleep than in the awake state. Changes in pupil diameter were coherent with both gamma-band power and blood volume in the somatosensory cortex, but the strength and sign of this relationship varied with arousal state. We observed a strong negative correlation between pupil diameter and both gamma-band power and blood volume during periods of awake rest and NREM sleep, although the correlations between pupil diameter and these signals became positive during periods of alertness, active whisking, and REM. Blinking was associated with increases in arousal and decreases in blood volume when the mouse was asleep. Bilateral coherence in gamma-band power and in blood volume dropped following awake blinking, indicating a reset of neural and vascular activity. Using only eye metrics (pupil diameter and eye motion), we could determine the arousal state of the mouse ('Awake,' 'NREM,' 'REM') with >90% accuracy with a 5 s resolution. There is a strong relationship between pupil diameter and hemodynamics signals in mice, reflecting the pronounced effects of arousal on cerebrovascular dynamics.SIGNIFICANCE STATEMENT Determining arousal state is a critical component of any neuroscience experiment. Pupil diameter and blinking are influenced by arousal state, as are hemodynamics signals in the cortex. We investigated the relationship between cortical hemodynamics and pupil diameter and found that pupil diameter was strongly related to the blood volume in the cortex. Mice were more likely to be awake after blinking than before, and blinking resets neural activity. Pupil diameter and eye motion can be used as a reliable, noninvasive indicator of arousal state. As mice transition from wake to sleep and back again over a timescale of seconds, monitoring pupil diameter and eye motion permits the noninvasive detection of sleep events during behavioral or resting-state experiments.

ASO Practice Guidelines Series: Management of Resectable, Borderline Resectable, and Locally Advanced Pancreas Cancer.

Pancreatic adenocarcinoma is an aggressive disease marked by high rates of both local and distant failure. In the minority of patients with potentially resectable disease, multimodal treatment paradigms have allowed for prolonged survival in an increasingly larger pool of well-selected patients. Therefore, it is critical for surgical oncologists to be abreast of current guideline recommendations for both surgical management and multimodal therapy for pancreas cancer. We discuss these guidelines, as well as the underlying data supporting these positions, to offer surgical oncologists a framework for managing patients with pancreatic adenocarcinoma.

Contemporary Outcomes of Grade-C Postoperative Pancreatic Fistula in a Nationwide Database.

INTRODUCTION: Grade-C postoperative pancreatic fistulas (POPFs) are dreaded complications following pancreaticoduodenectomy. The aim of this study was to quantify the incidence and risk factors associated with grade C POPF in a national database. METHODS: The National Surgical Quality Improvement Program targeted user files were queried for patients who underwent elective pancreaticoduodenectomy (2014-2020). Outcomes were compared between clinically relevant (CR) grade B POPF and grade C POPF. RESULTS: Twenty-six thousand five hundred fifty-two patients were included, of which 90.1% (n = 23,714) had No CR POPF, 8.7% (n = 2287) suffered grade B POPF, and 1.2% (n = 327) suffered grade C POPF. There was no change in the rate Grade-C fistula overtime (m = 0.06, P = 0.63), while the rate of Grade-B fistula significantly increased (m = +1.40, P < 0.01). Fistula Risk Scores were similar between grade B and C POPFs (high risk: 34.9% versus 31.2%, P = 0.21). Associated morbidity was increased with grade C POPF, including delayed gastric emptying, organ space infections, wound dehiscence, respiratory complications, renal complications, myocardial infarction, and bleeding. On multivariate logistic regression, diabetes mellitus (odds ratio: 1.41 95% confidence interval: 1.06-1.87, P = 0.02) was associated with grade C POPF. CONCLUSIONS: This study represents the largest contemporary series evaluating grade C POPFs. Of those suffering CR POPF, the presence of diabetes mellitus was associated with grade C POPF. While modern management has led to grade C POPF in 1% of cases, they remain associated with alarmingly high morbidity and mortality, requiring further mitigation strategies to improve outcomes.

Esophageal Lichen Planus: A Descriptive Multicenter Report.

GOALS: To better understand the characteristics, treatment approaches, and outcomes of patients with esophageal lichen planus (ELP). BACKGROUND: ELP is a rare, often unrecognized and misdiagnosed disorder. Data on this unique patient population are currently limited to small, single-center series. STUDY: A multicenter, retrospective descriptive study was conducted of adults diagnosed with ELP over a 5-year period, between January 1, 2015, and October 10, 2020, from 7 centers across the United States. RESULTS: Seventy-eight patients (average age 65 y, 86% female, 90% Caucasian) were included. Over half had at least 1 extraesophageal manifestation. Esophageal strictures (54%) and abnormal mucosa (50%) were frequent endoscopic findings, with the proximal esophagus the most common site of stricture. Approximately 20% had normal endoscopic findings. Topical steroids (64%) and/or proton pump inhibitors (74%) dominated management; endoscopic response favored steroids (43% vs. 29% respectively). Almost half of the patients required switching treatment modalities during the study period. Adjunctive therapies varied significantly between centers. CONCLUSIONS: Given its at times subtle clinical and endoscopic signs, a high index of suspicion and biopsy will improve ELP diagnosis, especially in those with extraesophageal manifestations. Effective therapies are lacking and vary significantly. Prospective investigations into optimal treatment regimens are necessary.

Defining the operative time threshold for safety in patients undergoing robotic pancreaticoduodenectomy.

BACKGROUND: Robotic pancreaticoduodenectomy (RPD) is a safe and efficacious procedure in appropriately selected patients, though frequently with increased operative times compared to open pancreaticoduodenectomy (OPD). METHODS: From 2014 to 2019, patients who underwent elective, low-risk, RPDs and OPDs in the NSQIP database were isolated. The operative time threshold (OTT) for safety in RPD patients was estimated by identifying the operative time at which complication rates for RPD patients exceeded the complication rate of the benchmark OPD control. RESULTS: Of 6270 patients identified, 939 (15%) underwent RPD and 5331 (85%) underwent OPD. The incidence of major morbidity or mortality for the OPD cohort was 35.1%. The OTT was identified as 7.7 h. Patients whose RPDs were above the OTT experienced a higher incidence of major morbidity (42.5% vs. 35.0%, p < 0.01) and 30-day mortality (2.7% vs. 1.2%, p = 0.03) than the OPD cohort. Preoperative obstructive jaundice (OR: 1.47, [95% CI: 1.08-2.01]) and pancreatic duct size <3 mm (OR: 2.44, [95% CI: 1.47-4.06]) and 3-6 mm (OR: 2.15, [95% CI: 1.31-3.52]) were risk factors for prolonged RPDs on multivariable regression. CONCLUSION: The operative time threshold for safety, identified at 7.7 h, should be used to improve patient selection for RPDs and as a competency-based quality benchmark.

High-frequency neuronal signal better explains multi-phase BOLD response.

Visual stimulation-evoked blood-oxygen-level dependent (BOLD) responses can exhibit more complex temporal dynamics than a simple monophasic response. For instance, BOLD responses sometimes include a phase of positive response followed by a phase of post-stimulus undershoot. Whether the BOLD response during these phases reflects the underlying neuronal signal fluctuations or is contributed by non-neuronal physiological factors remains elusive. When presenting blocks of sustained (i.e. DC) light ON-OFF stimulations to unanesthetized rats, we observed that the response following a decrease in illumination (i.e. OFF stimulation-evoked BOLD response) in the visual cortices displayed reproducible multiple phases, including an initial positive BOLD response, followed by an undershoot and then an overshoot before the next ON trial. This multi-phase BOLD response did not result from the entrainment of the periodic stimulation structure. When we measured the neural correlates of these responses, we found that the high-frequency band from the LFP power (300 - 3000 Hz, multi-unit activity (MUA)), but not the power in the gamma band (30 - 100 Hz) exhibited the same multiphasic dynamics as the BOLD signal. This study suggests that the post-stimulus phases of the BOLD response can be better explained by the high-frequency neuronal signal.

The Occurrence of Gastritis in Microscopic Colitis and Inflammatory Bowel Disease.

Multiple studies have shown that Helicobacter pylori infection is associated with a lower prevalence of inflammatory bowel disease (IBD).1,2 Besides chronic active gastritis (CAG) resulting from gastric infection with H pylori, pathologists have noticed another form of CAG, which is unrelated to H pylori infection and seems to cluster in patients with IBD.3-5 The aim of the present study was to compare the prevalence of H pylori-negative and H pylori-positive CAG in patients with IBD, and microscopic colitis (MC).

Intranasal gene therapy to prevent infection by SARS-CoV-2 variants.

SARS-CoV-2 variants have emerged with enhanced pathogenicity and transmissibility, and escape from pre-existing immunity, suggesting first-generation vaccines and monoclonal antibodies may now be less effective. Here we present an approach for preventing clinical sequelae and the spread of SARS-CoV-2 variants. First, we affinity matured an angiotensin-converting enzyme 2 (ACE2) decoy protein, achieving 1000-fold binding improvements that extend across a wide range of SARS-CoV-2 variants and distantly related, ACE2-dependent coronaviruses. Next, we demonstrated the expression of this decoy in proximal airway when delivered via intranasal administration of an AAV vector. This intervention significantly diminished clinical and pathologic consequences of SARS-CoV-2 challenge in a mouse model and achieved therapeutic levels of decoy expression at the surface of proximal airways when delivered intranasally to nonhuman primates. Importantly, this long-lasting, passive protection approach is applicable in vulnerable populations such as the elderly and immune-compromised that do not respond well to traditional vaccination. This approach could be useful in combating COVID-19 surges caused by SARS-CoV-2 variants and should be considered as a countermeasure to future pandemics caused by one of the many pre-emergent, ACE2-dependent CoVs that are poised for zoonosis.

Robotic-Assisted Minimally Invasive Esophagectomy: Postoperative Outcomes in a Nationwide Cohort.

INTRODUCTION: Robotic-assisted minimally invasive esophagectomy (RAMIE) in clinical trials has demonstrated improved outcomes compared to open esophagectomy (OE). However, outcomes after national implementation remain unknown. The aim of this study was to evaluate postoperative outcomes after RAMIE. METHODS: Patients who underwent elective esophagectomy between 2016 and 2020 were identified from the American College of Surgeons-- National Surgical Quality Improvement Program esophageal targeted participant user files and categorized by operative approach, with patients who underwent hybrid procedures excluded. Outcomes were compared between OE and minimally invasive esophagectomy (MIE)/RAMIE, with subset analyses by minimally invasive operative approach. Primary outcomes included pulmonary complications, anastomotic leak requiring reintervention, all-cause morbidity, and 30-d mortality. RESULTS: In total 2786 patients were included, of which 58.3% underwent OE, 33.2% underwent MIE, and 8.4% underwent RAMIE. In the entire cohort, Ivor Lewis esophagectomy was the most common technique (64.6%), followed by transhiatal (22.0%), and a McKeown technique (13.4%). Comparing OE and MIE/RAMIE, pulmonary complications (21.5% versus 16.1%, P < 0.01) and all-cause morbidity (40.9% versus 32.3%, P < 0.01) were both reduced in the MIE/RAMIE group. When directly comparing MIE to RAMIE, there was no difference in the rate of pulmonary complications, anastomotic leak, all-cause morbidity, and mortality. However, RAMIE was associated with decreased all-cause morbidity compared to OE (40.9% versus 33.3%, P = 0.03). CONCLUSIONS: RAMIE was associated with decreased morbidity compared to OE, with similar outcomes to MIE. The national adoption of RAMIE in this select cohort appears safe.

General Surgery Residency Virtual Recruitment During the Pandemic: An Analysis of Applicant Surveys.

INTRODUCTION: The COVID-19 pandemic forced a sudden change from in-person to virtual interviews for the general surgery residency match. General surgery programs and applicants adopted multiple strategies to best mimic in-person recruitment. The purpose of this study was to evaluate applicant opinions of the virtual recruitment format. MATERIALS AND METHODS: Postinterview survey responses for applicants interviewing at a single general surgery residency program in the 2020-2021 and 2021-2022 cycles were evaluated. All interviewed applicants were sent an anonymous survey assessing the virtual interview structure, their impression of the program, and their opinions on recruitment in the future. RESULTS: The response rate was 31.2% (n = 60). Most (88.4%) respondents reported a more favorable view of the program after a virtual interview. Factors that were most likely to create a favorable impression were residents (89.6%) and culture (81.0%). 50.8% of applicants favored virtual-only interviews. The majority of applicants (60.3%), however, preferred the virtual interview remain a component of the application process, 34.4% recommended that virtual interviews be used as an initial screen before in-person invites, while 19.0% suggested applicants should interview in-person or virtually without penalty. 62.1% favored capping the number of interviews offered by programs and accepted by applicants. CONCLUSIONS: The virtual interview format for general surgery residency allows applicants to effectively evaluate a residency program. Applicants are in favor of a combination of virtual and in-person interviews in the future. Innovation in the recruitment process, including limiting the number of applications and incorporating virtual events, is supported by applicants.

Incomplete Intestinal Metaplasia Is Rare in Autoimmune Gastritis.

BACKGROUND: Incomplete intestinal metaplasia (IM) is reportedly associated with higher gastric cancer (GC) risk than its complete variant. AGA Guidelines recommend including IM subtyping in routine pathology reports. This study assesses the prevalence of complete versus incomplete IM in gastric conditions with different GC risks. METHODS: IM subtyping (complete vs. incomplete) and grading (IM extension: G1: ≤30%; G2: >30%) were assessed in 386 patients with IM + ve gastric biopsy sets that included both antral and oxyntic samples. Cases were categorized as: (a) IM foci in otherwise normal mucosa (n = 59); (b) Helicobacter pylori gastritis (n = 138); (c) reactive gastropathy (141); and (d) autoimmune atrophic gastritis (AIG, n = 48). Odds ratios (OR) and their 95% CI were used in comparing the prevalence of incomplete IM and the correlation between subtype and IM extension. RESULTS: Incomplete IM was present in 37.7% of patients with H. pylori gastritis, 8.3% of those with AIG 5.0% of those with reactive gastropathy, and none of those with otherwise normal mucosa. Incomplete IM was strongly associated with more extensive (G2-IM) mucosal intestinalization (OR = 6.69; 95% CI = 2.77-9.40). CONCLUSION: Incomplete IM is significantly more prevalent in conditions (H. pylori gastritis) known to carry a higher risk of GC and is strongly associated with its extension. The low prevalence of incomplete IM in AIG (8.3%) and reactive gastropathy (5.2%) is in keeping with the low GC risk associated with these conditions.

Brain-wide ongoing activity is responsible for significant cross-trial BOLD variability.

A notorious issue of task-based functional magnetic resonance imaging (fMRI) is its large cross-trial variability. To quantitatively characterize this variability, the blood oxygenation level-dependent (BOLD) signal can be modeled as a linear summation of a stimulation-relevant and an ongoing (i.e. stimulation-irrelevant) component. However, systematic investigation on the spatiotemporal features of the ongoing BOLD component and how these features affect the BOLD response is still lacking. Here we measured fMRI responses to light onsets and light offsets in awake rats. The neuronal response was simultaneously recorded with calcium-based fiber photometry. We established that between-region BOLD signals were highly correlated brain-wide at zero time lag, including regions that did not respond to visual stimulation, suggesting that the ongoing activity co-fluctuates across the brain. Removing this ongoing activity reduced cross-trial variability of the BOLD response by ~30% and increased its coherence with the Ca2+ signal. Additionally, the negative ongoing BOLD activity sometimes dominated over the stimulation-driven response and contributed to the post-stimulation BOLD undershoot. These results suggest that brain-wide ongoing activity is responsible for significant cross-trial BOLD variability, and this component can be reliably quantified and removed to improve the reliability of fMRI response. Importantly, this method can be generalized to virtually all fMRI experiments without changing stimulation paradigms.

Feeding Jejunostomy Tube in Patients Undergoing Esophagectomy: Utilization and Outcomes in a Nationwide Cohort.

BACKGROUND: Feeding jejunostomy (JT) tubes are often utilized as an adjunct to optimize nutrition for successful esophagectomy; however, their utility has come into question. The aim of this study was to evaluate utilization and outcomes associated with JTs in a nationwide cohort of patients undergoing esophagectomy. METHODS: The NSQIP database was queried for patients who underwent elective esophagectomy. JT utilization was assessed between 2010 and 2019. Post-operative outcomes were compared between those with and without a JT on patients with esophagectomy-specific outcomes (2016-2019), with results validated using a propensity score-matched (PSM) analysis based on key clinicopathologic factors, including tumor stage. RESULTS: Of the 10,117 patients who underwent elective esophagectomy over the past decade, 53.0% had a JT placed concurrently and 47.0% did not. Utilization of JTs decreased over time, accounting for 60.0% of cases in 2010 compared to 41.7% in 2019 (m = - 2.14 95%CI: [- 1.49]-[- 2.80], p < 0.01). Patients who underwent JT had more composite wound complications (17.0% vs. 14.1%, p = 0.02) and a higher rate of all-cause morbidity (40.4% vs. 35.5%, p = 0.01). Following PSM, 1007 pairs were identified. Analysis of perioperative outcomes demonstrated a higher rate of superficial skin infections (6.1% vs. 3.5%, p = 0.01) in the JT group. However, length of stay, reoperation, readmission, anastomotic leak, composite wound complications, all-cause morbidity, and mortality rates were similar between groups. CONCLUSIONS: Among patients undergoing elective esophagectomy, feeding jejunostomy tubes were utilized less frequently over the past decade. Similar perioperative outcomes among matched patients support the safety of esophagectomy without an adjunct feeding jejunostomy tube.

Evaluation of BASE eConsult Manitoba: patient perspectives on the use of electronic consultation to improve access to specialty advice in Manitoba.

BACKGROUND: The burden of waiting to access specialist expertise may contribute to poorer health outcomes and causes distress for patients and providers. One solution to improve access to specialist care is to use innovative tools such as remote asynchronous electronic consultation (eConsult). Modeled after the Champlain BASE™ (Building Access to Specialist Advice) eConsult service, BASE™ eConsult Manitoba was launched in 2017 to help address long waits for patients to access specialist advice. OBJECTIVE: We aimed to evaluate patients' experiences after obtaining a BASE™ eConsult Manitoba service in their primary care setting. METHODS: Patients whose Primary Care Providers (PCPs) used BASE™ eConsult as part of their care were asked to participate and complete a telephone-based or online 29-question survey between January 2021 and October 2021. The survey questions were created in consultation with patient partners and based on questions asked in studies done in other jurisdictions. RESULTS: Of the 36 patients who chose to participate, 29 completed the entire survey (80%). Two-thirds (n = 22) agreed that eConsult has been helpful in their situation, and over 80% (n = 24) of participants agreed that eConsult was an acceptable way to access specialist care. During the visit when their PCP sent the eConsult, 7 patients were expecting to be referred to a specialist for a face-to-face consultation. Over half of all respondents (n = 15) reported that before the eConsult occurred, their PCP asked them what questions they wanted to be answered by the specialist. Almost all of these respondents' questions were fully answered by the eConsult. All of the respondents were satisfied with the experience of receiving an eConsult. CONCLUSION: Using eConsult is an acceptable way to improve access to specialist advice from patients' perspectives. Consideration should be given to expanding the use of eConsult services to improve access to specialist expertise for PCPs and their patients.

The Kidney Transplant Equity Index: Improving Racial and Ethnic Minority Access to Transplantation.

OBJECTIVES: To develop a scalable metric which quantifies kidney transplant (KT) centers' performance providing equitable access to KT for minority patients, based on the individualized prelisting prevalence of end-stage renal disease (ESRD). BACKGROUND: Racial and ethnic disparities for access to transplant in patients with ESRD are well described; however, variation in care among KT centers remains unknown. Furthermore, no mechanism exists that quantifies how well a KT center provides equitable access to KT for minority patients with ESRD. METHODS: From 2013 to 2018, custom datasets from the United States Renal Data System and United Network for Organ Sharing were merged to calculate the Kidney Transplant Equity Index (KTEI), defined as the number of minority patients transplanted at a center relative to the prevalence of minority patients with ESRD in each center's health service area. Markers of socioeconomic status and recipient outcomes were compared between high and low KTEI centers. RESULTS: A total of 249 transplant centers performed 111,959 KTs relative to 475,914 nontransplanted patients with ESRD. High KTEI centers performed more KTs for Black (105.5 vs 24, P <0.001), Hispanic (55.5 vs 7, P <0.001), and American Indian (1.0 vs 0.0, P <0.001) patients than low KTEI centers. In addition, high KTEI centers transplanted more patients with higher unemployment (52 vs 44, P <0.001), worse social deprivation (53 vs 46, P <0.001), and lower educational attainment (52 vs 43, P <0.001). While providing increased access to transplant for minority and low socioeconomic status populations, high KTEI centers had improved patient survival (hazard ratio: 0.86, 95% confidence interval: 0.77-0.95). CONCLUSIONS: The KTEI is the first metric to quantify minority access to KT incorporating the prelisting ESRD prevalence individualized to transplant centers. KTEIs uncover significant national variation in transplant practices and identify highly equitable centers. This novel metric should be used to disseminate best practices for minority and low socioeconomic patients with ESRD.

Photoacoustic imaging for microcirculation.

Microcirculation facilitates the blood-tissue exchange of nutrients and regulates blood perfusion. It is, therefore, essential in maintaining tissue health. Aberrations in microcirculation are potentially indicative of underlying cardiovascular and metabolic pathologies. Thus, quantitative information about it is of great clinical relevance. Photoacoustic imaging (PAI) is a capable technique that relies on the generation of imaging contrast via the absorption of light and can image at micron-scale resolution. PAI is especially desirable to map microvasculature as hemoglobin strongly absorbs light and can generate a photoacoustic signal. This paper reviews the current state of the art for imaging microvascular networks using photoacoustic imaging. We further describe how quantitative information about blood dynamics such as the total hemoglobin concentration, oxygen saturation, and blood flow rate is obtained using PAI. We also discuss its importance in understanding key pathophysiological processes in neurovascular, cardiovascular, ophthalmic, and cancer research fields. We then discuss the current challenges and limitations of PAI and the approaches that can help overcome these limitations. Finally, we provide the reader with an overview of future trends in the field of PAI for imaging microcirculation.

A National Assessment of T2 Staging for Intrahepatic Cholangiocarcinoma and the Poor Prognosis Associated with Multifocality.

BACKGROUND: T2 intrahepatic cholangiocarcinoma (ICC) is defined as a solitary tumors with vascular invasion or multifocal tumors including satellite lesions, multiple lesions, and intrahepatic metastases. This study aimed to evaluate the prognosis associated with multifocal tumors. METHODS: The National Cancer Database was queried from 2004 to 2017 for patients with non-metastatic ICC. The patients were grouped based on T2 staging, multifocality, and lymph node involvement. RESULTS: The study enrolled and classified 4887 patients into clinical (c) stage groups as follows: 15.2% with solitary T2N0 (sT2N0) tumors, 21.3% with multifocal T2N0 (mT2N0) tumors, and 63.5% with node-positive (TxN1) disease. Patients with (c)sT2N0 tumors had higher rates of surgical resection than those with (c)mT2N0 or (c)TxN1 disease (33.5% vs 19.7% vs 15.0%; p < 0.01). Median overall survival (OS) was better for the patients with (c)sT2N0 tumors than for those with multifocal and node-positive disease (15.4 vs 10.4 vs 10.4 months; p < 0.01). On multivariate analysis, (c)sT2N0 tumors were associated with better OS than (c)mT2N0 tumors [hazard ratio (HR), 1.31; 95% confidence interval (CI), 1.17-1.46; p < 0.01] or (c)TxN1 disease (HR,1.41; 95% CI 1.28-1.56; p < 0.01). In a subset analysis based on pathologic (p) staging of patients who underwent surgical resection with regional lymphadenectomy, multivariate analysis demonstrated that (p)sT2N0 tumors were associated with better OS than (p)mT2N0 tumors (HR,1.40; 95% CI 1.03-1.92; p = 0.03) or (p)TxN1 disease (HR, 2.05; 95% CI 1.62-2.58; p < 0.01). CONCLUSIONS: Multifocal T2N0 ICC is associated with poor OS and has a disparate prognosis compared with solitary T2N0 disease, even among patients who undergo resection. Future staging criteria should account for the poor outcomes associated with multifocal ICC.

Systemic Therapy for Resected Pancreatic Adenocarcinoma: How Much is Enough?

BACKGROUND: Systemic therapy is an essential part of treatment for pancreatic ductal adenocarcinoma (PDAC). However, not all patients receive every cycle of chemotherapy and even if they do, the impact of reduced dose density (DD) on survival is not known. PATIENTS AND METHODS: A single institutional prospective database was queried for patients with PDAC who underwent curative resection between 2009 and 2018. The primary outcome was DD, defined as the percentage of total planned chemotherapy actually received and associated survival. RESULTS: Of the 126 patients included, 38.9% underwent a neoadjuvant approach, which was associated with a greater median number of completed chemotherapy cycles (5 cycles versus 4 cycles, p < 0.01) and a higher median total DD (93.0% versus 65.0%, p < 0.01), compared with an adjuvant treatment approach. In both groups, adjuvant chemotherapy completion rates were low, with only 55 patients completing all adjuvant cycles. After sequential survival analysis, patients who received a DD ≥ 80% had improved median overall survival (OS) (27.1 months versus 18.6 months, p = 0.01), compared with patients who achieved a DD < 80%. On multivariate Cox proportional-hazards modeling, only the presence of lymphovascular invasion (HR: 1.77, 95% CI: 1.04-2.99, p = 0.04) and DD < 80% (HR: 1.91, 95% CI: 1.23-3.00, p = 0.01) were associated with decreased OS. CONCLUSIONS: In this cohort study, patients who received ≥ 80% DD had significantly better OS. DD should be considered an important prognostic metric in pancreatic cancer, and strategies are needed to improve chemotherapy tolerance to improve patient outcomes.

Is There a Benefit to Adjuvant Chemotherapy in Resected, Early Stage Pancreatic Ductal Adenocarcinoma?

BACKGROUND: The role of systemic therapy for Stage IA pancreatic ductal adenocarcinoma (PDAC) is unclear. The aim of our study was to evaluate the impact of adjuvant chemotherapy (AC) on survival in patients with early stage disease. METHODS: The National Cancer Database was queried from 2006 to 2017 for resected pT1N0M0 (Stage 1A) PDAC. Exclusion criteria included neoadjuvant therapy, radiation, or those who suffered a 90-day mortality. RESULTS: Of the 1526 patients included in the study, 42.2% received AC and 57.8% underwent surgery alone. Patients who received AC were younger, had fewer comorbidities, and were more likely to have private insurance, compared with those treated with surgery alone. Patients who received AC had longer median overall survival (OS) compared with those who underwent surgery alone (105.7 months vs 72.0 months, p < 0.01). Subset analyses based on individual "good" prognostic features (size ≤ 1.0 cm, lymphovascular invasion negative, well/moderately differentiated, margin negative resection) demonstrated improved OS with AC. Following propensity score matching based on key clinicopathologic features, AC remained associated with improved median OS (83.7 months vs 59.8 months, p < 0.01). However, in the cohort with body/tail tumors (101.2 months vs 95.0 months, p = 0.19) and those with all "good" prognostic features (95.9 months vs 90.6 months, p = 0.15), AC was not associated with improved survival. CONCLUSIONS: In resected, Stage IA PDAC, AC is associated with improved overall survival in the vast majority of patients; however, in select cohorts the role of AC is unclear. Further study is needed to tailor treatment to individual patients with PDAC.

Awake mouse brain photoacoustic and optical imaging through a transparent ultrasound cranial window.

Optical resolution photoacoustic microscopy (OR-PAM) can map the cerebral vasculature at capillary-level resolution. However, the OR-PAM setup's bulky imaging head makes awake mouse brain imaging challenging and inhibits its integration with other optical neuroimaging modalities. Moreover, the glass cranial windows used for optical microscopy are unsuitable for OR-PAM due to the acoustic impedance mismatch between the glass plate and the tissue. To overcome these challenges, we propose a lithium niobate based transparent ultrasound transducer (TUT) as a cranial window on a thinned mouse skull. The TUT cranial window simplifies the imaging head considerably due to its dual functionality as an optical window and ultrasound transducer. The window remains stable for six weeks, with no noticeable inflammation and minimal bone regrowth. The TUT window's potential is demonstrated by imaging the awake mouse cerebral vasculature using OR-PAM, intrinsic optical signal imaging, and two-photon microscopy. The TUT cranial window can potentially also be used for ultrasound stimulation and simultaneous multimodal imaging of the awake mouse brain.