Ssu72 phosphatase deficiency leads to spindle crossing during the second meiotic division process.

Ssu72 is a component of the yeast cleavage/polyadenylation factor (CPF) complex, which catalyzes the dephosphorylation of the C-terminal domain (CTD) of RNA polymerase II at S5-P and S7-P. It has been shown that Ssu72 phosphatase is involved in regulating chromosome cohesion during mitosis. To further clarify whether Ssu72 phosphatase affects chromosome separation during meiotic division in Schizosaccharomyces pombe, we utilized green fluorescent protein (GFP) to label centromeres and red fluorescent protein to label microtubule protein Atb2. The entire meiotic chromosome separation process of ssu72∆ cells was observed in real-time under fluorescence microscope. It was found that two spindles of ssu72∆ cells crossed during the metaphase and anaphase of the second meiotic division, and this spindle crossing led to a new type of spore defect distribution pattern. The results of this study can provide important reference significance for studying the roles of phosphatase Ssu72 in higher organisms.

Surgical management of gastroesophageal reflux disease in patients with systemic sclerosis.

BACKGROUND: Systemic sclerosis (scleroderma) is frequently associated with both gastroesophageal reflux disease (GERD) and simultaneous esophageal dysmotility. Anti-reflux procedures in this patient population must account for the existing physiology of each patient and likely disease progression. We aim to compare perioperative and intermediate outcomes of fundoplication versus gastric bypass for the treatment of GERD. METHODS: After IRB approval, patients with systemic sclerosis undergoing fundoplication or gastric bypass for the treatment of GERD from 2004 to 2016 were identified. Demographics, perioperative data, immediate complications, and symptom improvement were retrieved and analyzed. RESULTS: Fourteen patients with systemic sclerosis underwent surgical treatment of GERD during the defined study period. Average body mass index was 26 kg/m2. Seven fundoplications (2 Nissens, 4 Toupets, and 1 Dor) and 7 Roux-en-Y gastric bypasses (RYGB) were performed. No 30-day mortality was observed in either group. Median follow-up was 97 months for the fundoplication group (range 28-204 months), and 19 months for the RYGB group (range 1-164 months). Preoperatively, dysphagia, heartburn, and regurgitation were present in 71% (n = 10), 86% (n = 12), and 64% (n = 9) of patients, respectively. Eleven patients had pH study prior to surgical intervention, and 91% of them had abnormal acid exposure. Esophagitis was evident in 85% (n = 11) of patients during preoperative upper endoscopy, and two patients had Barrett's esophagus. Impaired esophageal motility was present in all RYGB patients and 71% of fundoplication patients. Of the patients who had assessment of their GERD symptoms at follow-up, all five patients in the RYGB group and only 3 (50%) patients in the fundoplication group reported symptom improvement or resolution. CONCLUSIONS: Laparoscopic RYGB as an anti-reflux procedure is safe and may provide an alternative to fundoplication in the treatment of GERD for systemic sclerosis patients with esophageal dysmotility.

Reoperative bariatric surgery for treatment of type 2 diabetes mellitus.

Primary bariatric surgery has been proven to be effective in weight loss and improvement of weight-related metabolic co-morbidities. However, a small proportion of patients after bariatric surgery either have persistent hyperglycemia or relapse after initial remission of their metabolic disease. Revisional bariatric surgery has been evaluated extensively for weight recidivism and postoperative complications. However, there has not been any high-level evidence validating the utility of revisional bariatric surgery on recurrent metabolic diseases, especially diabetes. In this review of 30 studies, we aimed to summarize the evidence and determine whether revisional surgery can have a positive impact on metabolic diseases that were not reversed by initial bariatric intervention. Overall, 14-38% of patients had residual diabetes at the time of revisional surgery. Depending on the index surgery and subsequent reconstruction, revisions induced 20-80% additional excess weight loss, or further decrease of body mass index by 10-30%. Improvement of diabetes was seen in 65-100% of patients. Specifically, conversion to Roux-en-Y gastric bypass (RYGB) yielded improvement of diabetes in 79%, 72%, and 62% of patients who previously had vertical banded gastroplasty (VBG), adjustable gastric banding (AGB), or sleeve gastrectomy (SG), respectively. Converting AGB to SG improved diabetes in 65% of patients, and SG to duodenal switch improved diabetes in 79% of patients. Revision of the gastric pouch or stoma in RYGB yielded improvement of diabetes in 79% of patients. Further clinical and mechanistic research is needed to better delineate the role of revisional bariatric surgery in patients with residual metabolic disease.

Successful Treatment of an Unusual Case of FPLD2: The Role of Roux-en-Y Gastric Bypass-Case Report and Literature Review.

Familial partial lipodystrophy type 2 (FPLD2) is a rare disorder associated with LMNA gene mutations. It is usually marked by loss of subcutaneous fat on the limbs and trunk and severe insulin resistance. Scattered reports have indicated that Roux-en-Y bypass helps to control the diabetes mellitus in these patients. We present here a very unusual patient with FPLD2 who had life-threatening retroperitoneal and renal fat accumulation accompanied by bilateral renal cancers. Following cryotherapy of one renal cancer and a contralateral nephrectomy with debulking of the retroperitoneal fat, Roux-en-Y gastric bypass (RYGB) has successfully controlled the disease for 3 years. The clinical presentations and causes of FPLD are reviewed and the role of RYGB is discussed.

E-cadherin dis-engagement activates the Rap1 GTPase.

E-cadherin based adherens junctions are finely regulated by multiple cellular signaling events. Here we show that the Ras-related Rap1 GTPase is enriched in regions of nascent cell-cell contacts and strengthens E-cadherin junctions: constitutively active Rap1 expressing MDCK cells exhibit increased junctional contact and resisted calcium depletion-induced cell-cell junction disruption. E-cadherin disengagement activated Rap1 and this correlated with E-cadherin association with the Rap GEFs, C3G and PDZ-GEF I. PDZ-GEF I associated with E-cadherin and beta-catenin whereas C3G interaction with E-cadherin did not involve beta-catenin. Knockdown of PDZ-GEF I in MDCK cells decreased Rap1 activity following E-cadherin junction disruption. We hereby show that Rap1 plays a role in the maintenance and repair of E-cadherin junctions and is activated via an "outside-in" signaling pathway initiated by E-cadherin and mediated at least in part by PDZ-GEF I.

Rap1a is a key regulator of fibroblast growth factor 2-induced angiogenesis and together with Rap1b controls human endothelial cell functions.

Angiogenesis, the formation of new blood vessels from existing vasculature, is regulated primarily by endothelial cell activity. We show herein that the Ras family GTPase Rap1 has a key role in the regulation of angiogenesis by modulating endothelial cell functions. Blood vessel growth into fibroblast growth factor 2 (FGF2)-containing Matrigel plugs was absent from rap1a(-/-) mice, and aortic rings derived from rap1a(-/-) mice failed to sprout primitive tubes in response to FGF2, when the tissue was embedded in Matrigel. Knocking down either rap1a or rap1b, two closely related rap1 family members, in human microvascular endothelial cells (HMVECs) by utilizing siRNA confirmed that Rap1 plays key roles in endothelial cell function. The rap1a or rap1b knockdown resulted in decreased adhesion to extracellular matrices and impaired cell migration. HMVEC monolayers lacking Rap1 had increased permeability, and Rap1-deficient endothelial cells failed to form three-dimensional tubular structures when they were plated on Matrigel in vitro. Finally, the activation levels of extracellular signal-regulated kinase (ERK), p38, and Rac, which are important signaling molecules in angiogenesis, were all reduced in response to FGF2 when either of the Rap1 proteins was depleted. These observations place Rap1 centrally in the human angiogenic process and suggest that both the Rap1a and Rap1b proteins are required for angiogenesis and that Rap1 is a critical mediator of FGF-induced ERK activation.

Rap1a null mice have altered myeloid cell functions suggesting distinct roles for the closely related Rap1a and 1b proteins.

The Ras-related GTPases Rap1a and 1b have been implicated in multiple biological events including cell adhesion, free radical production, and cancer. To gain a better understanding of Rap1 function in mammalian physiology, we deleted the Rap1a gene. Although loss of Rap1a expression did not initially affect mouse size or viability, upon backcross into C57BL/6J mice some Rap1a-/- embryos died in utero. T cell, B cell, or myeloid cell development was not disrupted in Rap1a-/- mice. However, macrophages from Rap1a null mice exhibited increased haptotaxis on fibronectin and vitronectin matrices that correlated with decreased adhesion. Chemotaxis of lymphoid and myeloid cells in response to CXCL12 or CCL21 was significantly reduced. In contrast, an increase in FcR-mediated phagocytosis was observed. Because Rap1a was previously copurified with the human neutrophil NADPH oxidase, we addressed whether GTPase loss affected superoxide production. Neutrophils from Rap1a-/- mice had reduced fMLP-stimulated superoxide production as well as a weaker initial response to phorbol ester. These results suggest that, despite 95% amino acid sequence identity, similar intracellular distribution, and broad tissue distribution, Rap1a and 1b are not functionally redundant but rather differentially regulate certain cellular events.