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result(s) for
"Heider, T. Ryan"
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Endoscopic Sphincterotomy Permits Interval Laparoscopic Cholecystectomy in Patients With Moderately Severe Gallstone Pancreatitis
by
Grimm, Ian S.
,
Brown, Alphonso
,
Heider, T. Ryan
in
Cholangiopancreatography, Endoscopic Retrograde
,
Cholangitis - etiology
,
Cholecystectomy
2006
Patients with moderately severe gallstone pancreatitis with substantial pancreatic and peripancreatic inflammation, but without organ failure, frequently have an open cholecystectomy to prevent recurrent pancreatitis. In these patients, prophylactic endoscopic retrograde cholangiography (ERC) with endoscopic sphincterotomy (ES) may prevent recurrent pancreatitis, permit laparoscopic cholecystectomy, and decrease risks. The medical records of all patients with pancreatitis undergoing cholecystectomy from 1999–2004 at the University of North Carolina Memorial Hospital were reviewed. Data regarding demographics, clinical course, etiology of pancreatitis, operative and endoscopic interventions, and outcome were extracted. Moderately severe gallstone-induced pancreatitis was defined as pancreatitis without organ failure but with extensive local inflammation. Thirty patients with moderately severe gallstone pancreatitis underwent ERC and ES and were discharged before cholecystectomy. Mean interval between ES and cholecystectomy was 102 ± 17 days. Cholecystectomy was performed laparoscopically in 27 (90%) patients, open in three (10%) patients, and converted to open in two (7%) patients, with a morbidity rate of 7% (two patients). No patient required drainage of a pseudocyst or developed recurrent pancreatitis. Interval complications resulted in hospital readmission in seven (23%) patients. In conclusion, recurrent biliary pancreatitis in patients with moderately severe gallstone pancreatitis is nil after ERC and ES. Hospital discharge of these patients permits interval laparoscopic cholecystectomy, but close follow-up is necessary in these potentially ill patients.
Journal Article
Acute Vagotomy Does Not Augment the Systemic Inflammatory Response in Patients with Peptic Ulcer Disease
by
Farrell, Timothy M.
,
Koruda, Mark J.
,
Heider, T. Ryan
in
Acute Disease
,
Adult
,
Biological and medical sciences
2004
Recent accumulating evidence suggests that the vagus nerve modulates the response to peripheral immunologic stimuli and that intact vagal mediation decreases the systemic inflammatory response. We hypothesized that patients who had vagotomy for complicated peptic ulcer disease would be at increased risk of an enhanced systemic inflammatory response compared to patients that did not have a vagotomy as part of their operative treatment. Ninety-six patients were identified from 1985 to 2000 and their medical records were reviewed. Patients were assigned to three groups based on the performance of a truncal vagotomy: truncal vagotomy (TV; N = 62 patients), nontruncal vagotomy (NTV; N = 34 patients), or a subgroup of the TV group, acute truncal vagotomy (ATV; N = 40 patients). Operative indications in the NTV and ATV groups were perforation (94% vs 47%) and bleeding (6% vs 53%). Systemic or organ-specific complications did not differ between groups (NTV vs ATV), and the sepsis (24% vs 23%) and mortality rates (29% vs 20%) were similar. The ICU and hospital length of stay did not differ substantially among the groups. This clinical study demonstrated that acute truncal vagotomy does not increase the risk of the systemic inflammatory response in surgical patients with complicated peptic ulcer disease.
Journal Article
Fundoplication Improves Disordered Esophageal Motility
2003
Patients with gastroesophageal reflux disease (GERD) and disordered esophageal motility are at risk for postoperative dysphagia, and are often treated with partial (270-degree) fundoplication as a strategy to minimize postoperative swallowing difficulties. Complete (360-degree) fundoplication, however, may provide more effective and durable reflux protection over time. Recently we reported that postfundoplication dysphagia is uncommon, regardless of preoperative manometric status and type of fundoplication. To determine whether esophageal function improves after fundoplication, we measured postoperative motility in patients in whom disordered esophageal motility had been documented before fundoplication. Forty-eight of 262 patients who underwent laparoscopic fundoplication between 1995 and 2000 satisfied preoperative manometric criteria for disordered esophageal motility (distal esophageal peristaltic amplitude ≤30 mm Hg and/or peristaltic frequency ≤80%). Of these, 19 had preoperative manometric assessment at our facility and consented to repeat study. Fifteen (79%) of these patients had a complete fundoplication and four (21%) had a partial fundoplication. Each patient underwent repeat four-channel esophageal manometry 29.5 ± 18.4 months (mean ± SD) after fundoplication. Distal esophageal peristaltic amplitude and peristaltic frequency were compared to preoperative data by paired
t test. After fundoplication, mean peristaltic amplitude in the distal esophagus increased by 47% (56.8 ± 30.9 mm Hg to 83.5 ± 36.5 mm Hg;
P < 0.001) and peristaltic frequency improved by 33% (66.4 ± 28.7% to 87.6 ± 16.3%;
P < 0.01). Normal esophageal motor function was present in 14 patients (74%) after fundoplication, whereas in five patients the esophageal motor function remained abnormal (2 improved, 1 worsened, and 2 remained unchanged). Three patients with preoperative peristaltic frequencies of 0%, 10%, and 20% improved to 84%, 88%, and 50%, respectively, after fundoplication. In most GERD patients with esophageal dysmotility, fundoplication improves the amplitude and frequency of esophageal peristalsis, suggesting refluxate has an etiologic role in motor dysfunction. These data, along with prior data showing that postoperative dysphagia is not common, imply that surgeons should apply complete fundoplication liberally in patients with disordered preoperative esophageal motility. (
J Gastrointest Surg 2003;7:159–163.)
Journal Article
Complete fundoplication is not associated with increased dysphagia in patients with abnormal esophageal motility
by
Farrell, Timothy M.
,
Koruda, Mark J.
,
Colliver, Craig C.
in
Deglutition Disorders - classification
,
Deglutition Disorders - diagnosis
,
Deglutition Disorders - etiology
2001
Abnormal esophageal motility is a relative contraindication to complete (360-degree) fundoplication because of a purported risk of postoperative dysphagia. Partial fundoplication, however, may be associated with increased postoperative esophageal acid exposure. Our aim was to determine if complete fundoplication is associated with increased postoperative dysphagia in patients with abnormal esophageal motor function. Medical records of 140 patients (79 females; mean age 48 ± 1.1 years) who underwent fundoplication for gastroesophageal reflux disease (GERD) were reviewed retrospectively to document demographic data, symptoms, and diagnostic test results. Of the 126 patients who underwent complete fundoplication, 25 met manometric criteria for abnormal esophageal motility (≤30 mm Hg mean distal esophageal body pressure or ≤80% peristalsis), 68 had normal esophageal function, and 33 had incomplete manometric data and were therefore excluded from analysis. Of the 11 patients who underwent partial fundoplication, eight met criteria for abnormal esophageal motility, two had normal esophageal function, and one had incomplete data and was therefore excluded. After a median follow-up of 2 years (range 0.5 to 5 years), patients were asked to report heartburn, difficulty swallowing, and overall satisfaction using a standardized scoring scale. Complete responses were obtained in 72%. Sixty-five patients who underwent complete fundoplication and had manometric data available responded (46 normal manometry; 19 abnormal manometry). Outcomes were compared using the Mann-Whitney U test. After complete fundoplication, similar postoperative heartburn, swallowing, and overall satisfaction were reported by patients with normal and abnormal esophageal motility. Likewise, similar outcomes were reported after partial fundoplication. This retrospective study found equally low dysphagia rates regardless of baseline esophageal motility; therefore a randomized trial comparing complete versus partial fundoplication in patients with abnormal esophageal motility is warranted.
Journal Article
A self-referenced in-situ arrival time monitor for X-ray free-electron lasers
2021
We present a novel, highly versatile, and self-referenced arrival time monitor for measuring the femtosecond time delay between a hard X-ray pulse from a free-electron laser and an optical laser pulse, measured directly on the same sample used for pump-probe experiments. Two chirped and picosecond long optical supercontinuum pulses traverse the sample with a mutually fixed time delay of 970 fs, while a femtosecond X-ray pulse arrives at an instant in between both pulses. Behind the sample the supercontinuum pulses are temporally overlapped to yield near-perfect destructive interference in the absence of the X-ray pulse. Stimulation of the sample with an X-ray pulse delivers non-zero contributions at certain optical wavelengths, which serve as a measure of the relative arrival time of the X-ray pulse with an accuracy of better than 25 fs. We find an excellent agreement of our monitor with the existing timing diagnostics at the SACLA XFEL with a Pearson correlation value of 0.98. We demonstrate a high sensitivity to measure X-ray pulses with pulse energies as low as 30
μ
J. Using a free-flowing liquid jet as interaction sample ensures the full replacement of the sample volume for each X-ray/optical event, thus enabling its utility even at MHz repetition rate XFEL sources.
Journal Article
A self-referenced in-situ arrival time monitor for X-ray free-electron lasers
by
Diez, Michael
,
Schulz, Sebastian
,
Hartmann, Nick
in
Femtosecond pulses
,
Free electron lasers
,
Time lag
2021
We present a novel, highly versatile, and self-referenced arrival time monitor for measuring the femtosecond time delay between a hard X-ray pulse from a free-electron laser and an optical laser pulse, measured directly on the same sample used for pump-probe experiments. Two chirped and picosecond long optical supercontinuum pulses traverse the sample with a mutually fixed time delay of 970 fs, while a femtosecond X-ray pulse arrives at an instant in between both pulses. Behind the sample the supercontinuum pulses are temporally overlapped to yield near-perfect destructive interference in the absence of the X-ray pulse. Stimulation of the sample with an X-ray pulse delivers non-zero contributions at certain optical wavelengths, which serve as a measure of the relative arrival time of the X-ray pulse with an accuracy of better than 25 fs. We find an excellent agreement of our monitor with the existing timing diagnostics at the SACLA XFEL with a Pearson correlation value of 0.98. We demonstrate a high sensitivity to measure X-ray pulses with pulse energies as low as 30 \\(\\mu\\)J. Using a free-flowing liquid jet as interaction sample ensures the full replacement of the sample volume for each X-ray/optical event, thus enabling its utility even at MHz repetition rate XFEL sources.
Ensemble learning of foundation models for precision oncology
by
Zhang, Xiaoming
,
Kelley, Yuan
,
Eweje, Feyisope
in
Artificial intelligence
,
Biomarkers
,
Ensemble learning
2025
Histopathology is essential for disease diagnosis and treatment decision-making. Recent advances in artificial intelligence (AI) have enabled the development of pathology foundation models that learn rich visual representations from large-scale whole-slide images (WSIs). However, existing models are often trained on disparate datasets using varying strategies, leading to inconsistent performance and limited generalizability. Here, we introduce ELF (Ensemble Learning of Foundation models), a novel framework that integrates five state-of-the-art pathology foundation models to generate unified slide-level representations. Trained on 53,699 WSIs spanning 20 anatomical sites, ELF leverages ensemble learning to capture complementary information from diverse models while maintaining high data efficiency. Unlike traditional tile-level models, ELF's slide-level architecture is particularly advantageous in clinical contexts where data are limited, such as therapeutic response prediction. We evaluated ELF across a wide range of clinical applications, including disease classification, biomarker detection, and response prediction to major anticancer therapies, cytotoxic chemotherapy, targeted therapy, and immunotherapy, across multiple cancer types. ELF consistently outperformed all constituent foundation models and existing slide-level models, demonstrating superior accuracy and robustness. Our results highlight the power of ensemble learning for pathology foundation models and suggest ELF as a scalable and generalizable solution for advancing AI-assisted precision oncology.