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Background: A greater than 1 mm tumour-free resection margin (R0 > 1 mm) is a prognostic factor in upfront-resected pancreatic ductal adenocarcinoma. After neoadjuvant treatment (NAT); however, the prognostic impact of resection margin (R) status remains controversial. Methods: Randomised and non-randomised studies assessing the association of R status and survival in resected pancreatic ductal adenocarcinoma after NAT were sought by systematic searches of MEDLINE, Web of Science and CENTRAL. Hazard ratios (HR) and their corresponding 95% CI were collected to generate log HR using the inverse-variance method. Random-effects metaanalyses were performed and the results presented as weighted HR. Sensitivity and meta-regression analyses were conducted to account for different surgical procedures and varying length of follow-up, respectively. Results: Twenty-two studies with a total of 4929 patients were included. Based on univariable data, R0 greater than 1 mm was significantly associated with prolonged overall survival (OS) (HR 1.76, 95% CI 1.57-1.97; P<0.00001) and disease-free survival (DFS) (HR 1.66, 95% CI 1.39-1.97; P< 0.00001). Using adjusted data, R0 greater than 1 mm was significantly associated with prolonged OS (HR 1.65, 95% CI 1.39-1.97; P<0.00001) and DFS (HR 1.76, 95% CI 1.30-2.39; P =0.0003). Results for R1 direct were comparable in the entire cohort; however, no prognostic impact was detected in sensitivity analysis including only partial pancreatoduodenectomies. Conclusion: After NAT, a tumour-free margin greater than 1 mm is independently associated with improved OS as well as DFS in patients undergoing surgical resection for pancreatic cancer. [ABSTRACT FROM AUTHOR]

The neurotransmitter GABA and its receptors assume essential functions during fetal and postnatal brain development. The last trimester of a human pregnancy and early postnatal life involves a vulnerable period of brain development. In the second half of gestation, there is a developmental shift from depolarizing to hyperpolarizing in the GABAergic system, which might be disturbed by preterm birth. Alterations of the postnatal GABA shift are associated with several neurodevelopmental disorders. In this in vivo study, we investigated neurogenesis in the dentate gyrus (DG) in response to daily administration of pharmacological GABAA (DMCM) and GABAB (CGP 35348) receptor inhibitors to newborn rats. Six-day-old Wistar rats (P6) were daily injected (i.p.) to postnatal day 11 (P11) with DMCM, CGP 35348, or vehicle to determine the effects of both antagonists on postnatal neurogenesis. Due to GABAB receptor blockade by CGP 35348, immunohistochemistry revealed a decrease in the number of NeuroD1 positive intermediate progenitor cells and a reduction of proliferative Nestin-positive neuronal stem cells at the DG. The impairment of hippocampal neurogenesis at this stage of differentiation is in line with a significantly decreased RNA expression of the transcription factors Pax6 , Ascl1 , and NeuroD1. Interestingly, the number of NeuN-positive postmitotic neurons was not affected by GABAB receptor blockade, although strictly associated transcription factors for postmitotic neurons, Tbr1 , Prox1 , and NeuroD2 , displayed reduced expression levels, suggesting impairment by GABAB receptor antagonization at this stage of neurogenesis. Antagonization of GABAB receptors decreased the expression of neurotrophins (BDNF , NT-3 , and NGF). In contrast to the GABAB receptor blockade, the GABAA receptor antagonization revealed no significant changes in cell counts, but an increased transcriptional expression of Tbr1 and Tbr2. We conclude that GABAergic signaling via the metabotropic GABAB receptor is crucial for hippocampal neurogenesis at the time of rapid brain growth and of the postnatal GABA shift. Differentiation and proliferation of intermediate progenitor cells are dependent on GABA. These insights become more pertinent in preterm infants whose developing brains are prematurely exposed to spostnatal stress and predisposed to poor neurodevelopmental disorders, possibly as sequelae of early disruption in GABAergic signaling. [ABSTRACT FROM AUTHOR]

Background: The omission of a prophylactic intra-abdominal drainage has been under debate in pancreatic surgery due to the high risk of complications and especially of postoperative pancreatic fistula (POPF). Recently, the second randomized controlled trial (RCT) and two propensity score-matched comparative studies assessing risks and benefits of a no-drainage policy versus prophylactic drainage after distal pancreatectomy (DP) have been published. This systematic review with meta-analysis provides an updated summary of the available evidence on this topic., Methods: RCTs and non-randomized comparative studies (NCS) investigating outcomes of no drainage versus drainage after DP were searched systematically in MEDLINE, Embase and CENTRAL. Random effects meta-analyses were performed, and the results presented as weighted odds ratios (OR) or mean differences (MD) with their corresponding 95% confidence intervals (c.i.). Subgroup analyses were performed to account for inter-study heterogeneity between RCTs and NCS., Results: Two RCTs and six NCS with a total of 3,610 patients undergoing DP were included of whom 1,038 (28.8%) patients did not receive prophylactic drainage. A no-drainage policy was associated with significantly lower risks of POPF (OR 0.38, 95% c.i. 0.25-0.56; P<0.00001), reduced major morbidity (OR 0.64, 95% c.i. 0.47-0.89; P=0.008), less reinterventions (OR 0.70, 95% c.i. 0.52-0.95; P=0.02) and fewer readmissions (OR 0.69, 95% c.i. 0.54-0.88; P=0.003) as well as shorter length of hospital stay (MD -1.74, 95% c.i. -2.70- -0.78; P=0.0004). Subgroup analyses including only RCTs confirmed benefits of the no-drainage policy., Conclusion: A no-drainage policy is associated with reduced POPF and morbidity and can therefore be recommended as standard procedure in patients undergoing DP., Competing Interests: Category in which the article is being submitted: Systematic Review and Meta-Analysis. No sources of funding. This paper is not based on a previous communication to a society or meeting. The authors declare no conflict of interest. Data are available on request., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

The neurotransmitter GABA and its receptors assume essential functions during fetal and postnatal brain development. The last trimester of a human pregnancy and early postnatal life involves a vulnerable period of brain development. In the second half of gestation, there is a developmental shift from depolarizing to hyperpolarizing in the GABAergic system, which might be disturbed by preterm birth. Alterations of the postnatal GABA shift are associated with several neurodevelopmental disorders. In this in vivo study, we investigated neurogenesis in the dentate gyrus (DG) in response to daily administration of pharmacological GABA A (DMCM) and GABA B (CGP 35348) receptor inhibitors to newborn rats. Six-day-old Wistar rats (P6) were daily injected (i.p.) to postnatal day 11 (P11) with DMCM, CGP 35348, or vehicle to determine the effects of both antagonists on postnatal neurogenesis. Due to GABA B receptor blockade by CGP 35348, immunohistochemistry revealed a decrease in the number of NeuroD1 positive intermediate progenitor cells and a reduction of proliferative Nestin-positive neuronal stem cells at the DG. The impairment of hippocampal neurogenesis at this stage of differentiation is in line with a significantly decreased RNA expression of the transcription factors Pax6 , Ascl1 , and NeuroD1 . Interestingly, the number of NeuN-positive postmitotic neurons was not affected by GABA B receptor blockade, although strictly associated transcription factors for postmitotic neurons, Tbr1 , Prox1 , and NeuroD2 , displayed reduced expression levels, suggesting impairment by GABA B receptor antagonization at this stage of neurogenesis. Antagonization of GABA B receptors decreased the expression of neurotrophins (BDNF , NT-3 , and NGF) . In contrast to the GABA B receptor blockade, the GABA A receptor antagonization revealed no significant changes in cell counts, but an increased transcriptional expression of Tbr1 and Tbr2 . We conclude that GABAergic signaling via the metabotropic GABA B receptor is crucial for hippocampal neurogenesis at the time of rapid brain growth and of the postnatal GABA shift. Differentiation and proliferation of intermediate progenitor cells are dependent on GABA. These insights become more pertinent in preterm infants whose developing brains are prematurely exposed to spostnatal stress and predisposed to poor neurodevelopmental disorders, possibly as sequelae of early disruption in GABAergic signaling., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Gustorff, Scheuer, Schmitz, Bührer and Endesfelder.)