Steric Influences on Chain Microstructure in Palladium-Catalyzed α-Olefin (Co)polymerization: Unveiling the Steric-Deficient Effect.

This study addresses the challenge of controlling branching density and branch-type distribution in late-transition-metal-catalyzed chain walking polymerizations. We explored α-diimine Pd(II) complexes with incrementally increased ortho-aryl sterics for long-chain α-olefin (co)polymerization. Pd0-Pd3 catalysts, which feature gradually increased ortho-aryl sterics and at least one small CH3 substituent, exhibited similar 2,1-insertion fractions (44-50%), polymer branching densities (55-63/1000C), and melting temperatures (26-28 °C). In contrast, Pd4 with bulky ortho-aryl sterics covering all sides demonstrated a significant increase in 2,1-insertion fractions up to 82%, leading to "PE-like" polymers with high melting temperatures (Tm > 111 °C). This abrupt change in polymerization behavior, termed the "steric-deficient effect", contrasts with the gradual changes observed in similar Ni(II) systems that we reported previously. Furthermore, due to the rapid chain walking ability of Pd(II) catalysts in long-chain α-olefin (co)polymerization, these catalysts favor the production of polyolefins with higher proportions of methyl branches compared to those produced by Ni(II) catalysts. Particularly, these Pd(II) catalysts are capable of synthesizing functionalized semicrystalline copolymers by copolymerizing 1-octene with a variety of polar comonomers, thereby significantly altering the surface properties of the materials.

Knowledge, attitudes, and practices among Chinese reproductive-age women toward uterine adenomyosis.

Objective: This study aimed to assess the knowledge, attitudes and practices (KAP) among Chinese reproductive-age women toward uterine adenomyosis. Methods: This web-based cross-sectional study was conducted between April 2023 and September 2023 at the Second Hospital of Hebei Medical University. A self-designed questionnaire was developed to collect demographic information of reproductive-age women, and assess their KAP toward uterine adenomyosis. Results: A total of 520 valid questionnaires were collected. Among the participants, 127 (24.42%) were diagnosed with uterine adenomyosis, and 120 (23.08%) were accompanied by uterine fibroids. The mean knowledge, attitudes and practices scores were 3.54 ± 3.72 (possible range:0-10), 20.96 ± 3.19 (possible range:5-25) and 24.01 ± 4.95 (possible range:7-35), respectively. The structural equation model demonstrated that knowledge had direct effects on attitudes and practices, as indicated by a path coefficient of 0.714 (p < 0.001) and 1.510 (p < 0.001), respectively. Moreover, attitudes had direct effects on practices, with a path coefficient of 0.226 (p = 0.001). Conclusion: The findings revealed that reproductive-age women have insufficient knowledge, negative attitudes, and poor practices toward the uterine adenomyosis. Comprehensive training programs are needed to improve reproductive-age women practices in this area.

Colorectal cancer tumor stem cells mediate bevacizumab resistance through the signal IL-22-STAT3 signaling pathway.

Bevacizumab is the standard treatment for colorectal cancer (CRC) in the advanced stage. However, poor diagnosis identified due to the bevacizumab resistance in many CRC patients. Previous studies have found that CRC stem cells (CCSCs) and interleukin 22 (IL-22) are involved in the resistance of bevacizumab, however, the mechanism of remains unclear. In this study, we established the bevacizumab drug-resistant cell line HCT-116-R by concentration gradient method, and the cell viability was detected by CCK-8 assay. The resistance of bevacizumab in CRC cell lines HCT-116-R was identified by characterizing epithelial-mesenchymal transition (EMT). Additionally, HCT-116-R cell lines were isolated from CCSCs and their tumorigenicity was validated in nude mice. We observed that that compared with the matched group, the expression of IL-22, IL-22R, STAT3, and GP130 in drug-resistant cells increased distinctly, with blocked IL-22 cells were successfully constructed by lentiviral interference. The level of proteins in stem cell landmarks (EpCAM, CD133), and stem cell landmarks (Oct4, Sox2) was identified by western blotting. Furthermore, the IL-22 role was evaluated by xenograft model. We found that short hairpin RNA (shRNA) suppression of IL-22 expression can restore the sensitivity of drug-resistant CCSCs to bevacizumab, Moreover, xenograft tumor models show that suppression of IL-22 can increase the anti-tumor influence of bevacizumab. In summary, we demonstrated that CCSCs play a major part in bevacizumab-resistant CRC. Inhibiting the signaling pathway of IL-22/STAT3 can improve the anti-tumor influence on bevacizumab in vitro and in vivo. Thus, IL-22 may represent a new anti-bevacizumab target in CRC.

Seminal vesicle metastasis after liver transplantation for hepatocellular carcinoma: A case report.

RATIONALE: Cancer recurrence and metastasis after liver transplantation (LT) is common in some hepatocellular carcinoma (HCC) patients. The most common sites of extrahepatic metastases are lung, regional lymph node, adrenal gland, and bone. To our knowledge, HCC metastasis to the seminal vesicle after LT has not been reported in the literature. PATIENT CONCERNS: A 56-year-old Asian man presented at hospital with a 9-year history of orthotopic LT because of HCC. The patient underwent surgery and radiotherapy for HCC metastasis to adrenal gland and 1 year later, chemotherapy for peritoneal metastasis. A few months later, the patient presented with computed tomography (CT) image showing masses in right lobe of liver, seminal vesicle, and space occupying mass between the spleen and stomach. DIAGNOSES: Combination of clinical and pathological features revealed the seminal vesicle mass as metastasis from HCC. INTERVENTIONS: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for liver and seminal vesicle lesions was performed and the postoperative pathology revealed malignancy. Thus, the patient underwent surgery and the diagnosis of seminal vesicle metastasis of HCC was confirmed by pathology and immunohistochemical analysis. OUTCOMES: The patient died due to systemic failure. LESSONS: Seminal vesicle metastasis from HCC after LT is rare and there is no consensus on its treatment. Further research into the pathogenesis and therapy of seminal vesicle from HCC after LT is needed to improve outcomes in the rare disease.

[The management of laryngotracheal defect derived from thyroid gland papillary carcinoma resection].

OBJECTIVE: To investigate the preservation of the structure and function of the trachea and larynx, the management of laryngotracheal defect when trachea and larynx was involved. METHOD: To review the management and clinical results of 13 cases of thyroid papillary carcinoma with larynx and trachea involvement, the preservation of laryngotracheal structure and relative defect reconstruction of our department from 2007-2014. Those patients being performed total laryngectomy was excluded. 3 males and 10 females, aged from 46 to 67 years old with median age of 53 were included. Among them 8 cases were recurrent. The extent of the tumor foci was estimated with the help of computed tomography and laryngofiberoscope before surgery. Selective neck dissection, total thyroidectomy and related laryngotracheal resection was performed for the first time operation patient, while selective neck dissection, recurrent foci and related larynx and trachea resection was performed for those recurrent patients. Three kinds of modalities were applied to manage the laryngotracheal defect including to reconstruct with pedicled sternocleidomastoid clavicular periosteocutaneous flap, pedicled trapizius muscular flap and to preserve the remaining larynx and trachea and perform a stoma of larynx and trachea which repaired by a second-stage procedure. The patients were followed-up from half an year to 3 years. RESULT: Ten patients out of 13 decannulated while another 3 cases, 2 of which were performed local flap to reduce the stoma, wore tracheal tubes all time. CONCLUSION: Either flap transfer or laryngotracheal stoma before second stage repair might preserve partial laryngotacheal anatomy and function in selected cases thus improve the life quality of the patients.

[Priliminary study of pedicled sternocleidomastoid clavicular periosteocutaneous flap to repair the laryngotracheal defect].

OBJECTIVE: To investigate the feasibility of utilizing pedicled sternocleidomastoid clavicular periosteocutaneous flap to reconstruct the laryngotracheal defect after tumor resection. METHOD: To review 6 cases of laryngotracheal defect resulting from resction of thyroid papillary carcinoma(4/6) or subglottic laryngeal carcinoma (2/6) (T1~2N1~2M0 , UICC,2002), laryngotracheal stenting was also employed in all cases. Half a year after surgery, the stoma was sutured if no local recurrence took place and safety was proved after tracheal tube had been obstructed for days. The follow-up time lasted from half a year to 3 years. RESULT: Four cases (4/6) were extubated successfully without event, one case could intermittently plug the tracheal tube. One patient couldn't breath with tracheal tube plugging. CONCLUSION: To reconstruct the laryngotracheal defect with pedicled sternocleidomastoid clavicular.periosteocutaneous flap after tumor resection is feasible in selected cases and could get satisfactory clinical results either in respiration or phonation.

[Laryngo-tracheal flap to reconstruct the defect after resection of the hypopharyngeal carcinoma with cervical esophagus involvement].

OBJECTIVE: To investigate cervical esophageal reconstruction by means of laryngo-tracheal flap after resection of hypopharyngeal carcinoma with cervical esophageal involvement. METHOD: Eleven cases of hypopharyngeal carcinoma with cervical esophageal involvement. Unilateral piriform sinus and cervical esophagus were involved in 8 cases (8/11) while bilateral piriform sinus, posterior pharyngeal wall and cervical esophagus were involved in 3 cases. After resection of laryngeal, pharyngeal and esophageal tumors and bilateral neck dissection, direct anastomosis of larynx and trachea with esophagus of cervico-thoracic segment was performed if circular structure of larynx and trachea could be preserved (3/11), pectoralis major myocutaneous flap was employed if only part of pharynx and larynx could be preserved (8/11). Postoperative radiochemotherapy was adopted and follow-up lasted for 1-5 years. RESULT: All cases healed without event except for one case of pharyngeal fistula and one case of chylous fistula which also healed after about 2 weeks dressing change. All patients got normal diet without anastomotic stricture. There was no recurrence in 6 patients at the 3 years follow-up, 4 patients had metastases in the neck and 1 patient had thoracic esophageal carcinoma with hepatic metastasis arid gave up further treatment. The overall 3-year survival rate was 54.5%. CONCLUSION: Using laryngo-tracheal flap to reconstruct cervical esophagus after resection of hypopharyngeal carcinoma with cervical esophageal involvement is a recommendable method that is simple in processing, reliable in effect and less in postoperative complications.

Effect of postoperative fractionated radiotherapy on canine ePTFE graft neointima and anastomotic stoma healing: a preliminary experimental study.

OBJECTIVE: The present study aimed to determine whether postoperative fractionated radiotherapy, at a total dose of 35 Gy, affected expanded polytetrafluoroethylene (ePTFE) graft anastomotic stoma healing and neointima formation. METHODS: The subrenal abdominal aortas of 20 mongrel dogs were replaced with an ePTFE graft. The dogs were randomly divided into either a radiotherapy or nonradiotherapy control group. Grafts were harvested at 4 or 8 weeks after surgery. Hematoxylin-eosin staining, and immunohistochemistry tests for proliferating cell nuclear antigen (PCNA) and CD34 were undertaken to analyze the anastomotic healing and neointima formation. RESULTS: The patency rate of grafts was 100% in each group. No disunion, rupture, or aneurysm was observed in the anastomotic stoma. Eight weeks after surgery, the graft neointima and anastomotic vessel wall of the radiotherapy group were significantly thinner than those of the control group (p < 0.05). Immunohistochemical examination was carried out in accordance with histomorphology. CONCLUSION: Postoperative fractionated radiotherapy after an ePTFE graft replacement of the abdominal aorta did not affect the healing of the anastomotic stoma. However, it suppressed the development of hyperplasia in the anastomotic stoma neointima and graft neointima formation in the short term.