Biomedical subjects

Siyu Sun

Publications and source records attributed to Siyu Sun.

4 recordsLinked to original sources

PubMed2025

Repeats mimic pathogen-associated patterns across a vast evolutionary landscape.

An emerging hallmark of many human diseases is transcription of typically silenced repetitive DNA containing pathogen-associated molecular patterns (PAMPs). These PAMPs engage the innate immune system via pattern recognition receptors (PRRs)-a phenomenon known as viral mimicry. We propose a statistical physics framework to quantify viral mimicry by measuring "selective forces" that enrich PAMPs compared to a genome-wide reference distribution. We validate our predictions by identifying repeats that bind different PRRs and show potential viral mimics in different repeat families across eukaryotic genomes, suggesting shared mechanisms drive emergence and retention. We propose two non-exclusive evolutionary hypotheses. The first "repeat-centric" hypothesis posits PAMPs are integral to the repeat life cycle and are therefore enriched as they mediate repeat expansion. The second "organism-centric" hypothesis proposes viral mimicry functions as a cell-intrinsic feedback mechanism for sensing and reacting to transcriptional dysregulation, which provides a selective pressure to maintain PAMPs in genomes.

Humans↗

PubMed2006

Endoscopic band ligation of small gastric stromal tumors and follow-up by endoscopic ultrasonography.

BACKGROUND: Gastrointestinal stromal tumor (GIST) is a relatively common gastric submucosal tumor with potential for malignant transformation. The efficacy of a new method for resection of these tumors, endoscopic band ligation, was evaluated. METHODS: The study included 29 patients with small gastric stromal tumors arising in the gastric muscularis propria as determined by endoscopy, endoscopic ultrasonography (EUS), and deep endoscopic biopsies. A standard endoscope with a transparent cap attached to the tip was used. The cap was placed over the lesion, maximum sustained suction was applied, and an elastic band was released around the base. Beginning two weeks after banding, the lesions were observed endoscopically once per week until healing was complete. Thereafter, all patients underwent EUS every two to three months on schedule. RESULTS: The 28 GISTs sloughed completely. The mean time required for complete healing after band ligation was 4.8 weeks. One lesion did not slough because they were not completely ligated. The lesion was ligated for the second time and sloughed completely. Bleeding occurred in one patient three days after ligation because the lesion sloughed early. The bleeding was managed successfully with metallic clips. No perforation and other complications occurred. Followup ranged from 36 to 51 months, during which time only one recurrence was observed four months postoperatively. CONCLUSIONS: Endoscopic band ligation with systematic followup by EUS is an effective and safe treatment for small GISTs.

Adult↗

PubMed2005

EUS-guided interstitial brachytherapy of the pancreas: a feasibility study.

BACKGROUND: Intraoperative interstitial brachytherapy has been effective when used at laparotomy to improve local control in locally advanced pancreatic cancer. Our aim in this study was to investigate the feasibility and the safety of EUS-guided brachytherapy of the pancreas in a porcine model. METHODS: A modified 18-gauge needle with radioactive seeds was inserted, under EUS guidance, into the pancreas. The radioactive seeds were implanted into the tissue by the needle. After 14 days of clinical observation, the animals were euthanized, and the tissue response to brachytherapy was examined. OBSERVATIONS: All the seeds were successfully implanted, and no migration occurred. Localized tissue necrosis and fibrosis was achieved in the pancreas, without significant complication. One pig had mild hyperlipasemia. Biochemical parameters were normal in the remaining pigs. CONCLUSIONS: EUS-guided implantation of radioactive seeds is a safe, simple, and minimally invasive technique for interstitial brachytherapy.

Animals↗

PubMed2004

Endoscopic band ligation without electrosurgery: a new technique for excision of small upper-GI leiomyoma.

BACKGROUND: Leiomyoma is a relatively common submucosal tumor in the upper-GI tract. The efficacy of a new method for resection of these tumors, endoscopic band ligation, was evaluated. METHODS: The study included 59 patients with 64 small upper-GI leiomyomas arising in the muscularis propria as determined by endoscopy, EUS, and EUS-guided FNA. The distribution of the 64 leiomyomas was the following: esophageal, 50; gastric, 12; duodenal, 2. A standard endoscope with a transparent cap attached to the tip was used. The cap was placed over the lesion, maximum sustained suction was applied, and an elastic band was released around the base. Beginning 2 weeks after banding, the lesions were observed endoscopically once per week until healing was complete. RESULTS: The 50 esophageal leiomyomas sloughed completely. The mean time required for complete healing after band ligation was 3.6 weeks. Nine of the 12 gastric leiomyomas sloughed completely; the resulting ulcer defect was healed at a mean of 4.5 weeks. The other 3 lesions did not slough because they were not completely ligated. The two duodenal lesions sloughed completely after banding, and the mean time until healing of the defect was 4.5 weeks. No perforation occurred. Follow-up ranged from 16 to 31 months, during which time no recurrence was observed. CONCLUSIONS: Endoscopic band ligation is an effective and safe treatment for small upper-GI leiomyoma.

Adult↗