Surjective isometries on an algebra of analytic functions with CnC^n-boundary values (Research on preserver problems on Banach algebras and related topics)

Let , ⁻ and be the open unit disk, closed unit disk and unit circle in ℂ. Let $A^n$(⁻) denote the algebra of all continuous functions f on ⁻ which are analytic in and whose restrictions f| to T are of class $C^n$. For each f ∈ $A^n$(⁻), the k-th derivative of f| as a function on is denoted by D^k(f). We characterize surjective, not necessarily linear, isometries on $A^n$(⁻) with respect to the norm ∥f∥⁻ + Σ[n][k=1]∥$D^k$(f)∥/k!, where ∥ · ∥⁻ and ∥ · ∥ are the supremum norms on ⁻ and , respectively

Surjective isometries between unitary sets of unital JB∗-algebras

We would like to thank Prof. Lajos Molnár for encouraging us to explore this problem. We are also indebted to the anonymous reviewer for several useful comments. First and fifth authors partially supported by the Spanish Ministry of Science, Innovation and Universities (MICINN) and European Regional Development Fund project no. PGC2018-093332-B-I00, Programa Operativo FEDER 2014-2020 and Consejería de Economía y Conocimiento de la Junta de Andalucía grant numbers A-FQM-242-UGR18 and FQM375. First author partially supported by EPSRC (UK) project “Jordan Algebras, Finsler Geometry and Dynamics” ref. no. EP/R044228/1. Second author partially supported by JSPS KAKENHI Grant Number JP 21J21512. Fourth author partially supported by JSPS KAKENHI (Japan) Grant Number JP 20K03650. * Funding for open access charge: Universidad de Granada / CBUAThis paper is, in a first stage, devoted to establishing a topological–algebraic characterization of the principal component, U0(M), of the set of unitary elements, U(M), in a unital JB⁎-algebra M. We arrive to the conclusion that, as in the case of unital C⁎-algebras, U0(M)=M1−1∩U(M)={Ue⋯Ue(1):n∈N,hj∈Msa∀1≤j≤n}={u∈U(M): there exists w∈U0(M) with ‖u−w‖<2} is analytically arcwise connected. Actually, U0(M) is the smallest quadratic subset of U(M) containing the set eiM. Our second goal is to provide a complete description of the surjective isometries between the principal components of two unital JB⁎-algebras M and N. Contrary to the case of unital C⁎-algebras, we shall deduce the existence of connected components in U(M) which are not isometric as metric spaces. We shall also establish necessary and sufficient conditions to guarantee that a surjective isometry Δ:U(M)→U(N) admits an extension to a surjective linear isometry between M and N, a conclusion which is not always true. Among the consequences it is proved that M and N are Jordan ⁎-isomorphic if, and only if, their principal components are isometric as metric spaces if, and only if, there exists a surjective isometry Δ:U(M)→U(N) mapping the unit of M to an element in U0(N). These results provide an extension to the setting of unital JB⁎-algebras of the results obtained by O. Hatori for unital C⁎-algebras.CBUAConsejería de Economía y Conocimiento de la Junta de Andalucía A-FQM-242-UGR18, FQM375Ministerio de Ciencia, Innovación y UniversidadesEngineering and Physical Sciences Research Council EP/R044228/1Universidad de GranadaMinisterio de Ciencia e InnovaciónJapan Society for the Promotion of Science JP 20K03650, JP 21J21512European Regional Development Fund PGC2018-093332-B-I0

Advantage of Long Ileus-tube Placement by Gastrostomy for Treating Patients with Refractory Intestinal Obstruction

Maintaining a long transnasal ileus tube for a long period can be quite painful for patients such as in those with refractory intestinal obstruction and peritonitis carcinomatosa and it can markedly decrease quality of life (QOL) due to unexpected respiratory complications associated with the tube placement. To mitigate such complications, we undertook a trial insertion of a long ileus tube by gastrostomy in five patients with refractory intestinal obstruction (four cases of peritonitis carcinomatosa and one case of chronic intestinal pseudo-obstruction). We inserted the transgastric ileus tube using a percutaneous gastrostomy catheter kit after puncture with a plastic skin (PS) needle covered with a protective sheath, and then endoscopically placed the tube beyond the ligament of Treitz. Subsequently, we removed the long transnasal ileus tube, and comparable decompression was achieved. In all cases, the entire procedure was easily performed with no complications. Moreover, patients experienced reduced pain and stress and they were able to regain some freedom during activity

Comparison of Surgeon Stress and Workload between Reduced-port and Laparoscopic Cholecystectomy : A Prospective Study

Single-port laparoscopic surgery（SPLS）has attracted attention in the field of minimally invasive surgery; however, the associated technical difficulty has delayed its adoption by all surgeons. Reduced-port laparoscopic surgery might be easier to perform than SPLS, and in this prospective study, we compared surgeon stress and workload between reduced-port laparoscopic cholecystectomy（RPLC）and conventional laparoscopic cholecystectomy（CLC）. Twenty consecutive patients were assigned to undergo either RPLC or CLC between July 2016 and April 2017. Two surgeons performed the operations. The differences in surgeon workload and stress between RPLC and CLC were evaluated. Patient factors and operative outcomes were not significantly different between RPLC and CLC. In the surgeon-reported Surgery Task Load Index, the task demand subscale was significantly higher for RPLC than for CLC（P＝0.005）, although the salivary amylase levels were not significantly different between RPLC and CLC. RPLC was similar to CLC with respect to surgeon stress. Considering workload, the task demand was higher in CLC than in RPLC, which therefore might be an acceptable alternative to CLC for treating benign gallbladder disease

The Prognosis for Unexpected Gallbladder Carcinoma with Bile Spillage during Laparoscopic Cholecystectomy

Here we review the prognosis of patients with unsuspected gallbladder carcinoma（GBC）, detected after laparoscopic cholecystectomy（LC）in a single institute. We reviewed the medical records of patients diagnosed with gallbladder stones on admission, who underwent LC. Carcinoma involving the gallbladder was found in 22 of 2,770 patients（0.9％）via postoperative pathological examination. This GBC group spanned 58-87 years of age（mean, 75 years; 13 females and 9 males）. The preoperative diagnosis was gallbladder stones with acute/chronic cholecystitis or adenomyomatosis of the gallbladder in all patients. We performed an additional surgery in 6 of 15 patients with pT2 and T3 disease; of these, 3 patients with pT2 disease and 1 with pT3 experienced bile spillage during the LC. The mean survival of patients with unexpected GBC was 21 months, with bile spillage occurring as a complication of LC identified as a potential risk factor for shorter survival（15.3 vs. 32.5 months）. We identified patients with pT2 and pT3 disease after LC, and two patients with pT2 and 1 with pT3 who had bile spillage during LC died of peritoneal dissemination within 28 months, despite additional surgery. Occasional seeding caused by bile spillage during LC should be carefully avoided to minimize the risk of developing unsuspected GBC after LC

The Surgical Benefits of Repeat Hepatectomy for Colorectal Liver Metastasis

The most common site of distant metastasis from colorectal cancer is the liver, and hepatectomy presents the best curative treatment for recurrence of colorectal liver metastasis （CRLM）. This study aimed to identify factors of prognostic value for repeat hepatectomy for CRLM and to determine whether a third such procedure could similarly produce favourable outcomes for CRLM. We analyzed data for 161 patients in our department with colorectal metastasis. Of these, 22 patients underwent repeat hepatectomy for recurrent metastasis, with 16 undergoing a second hepatectomy and 6 a third hepatectomy. We analyzed patient characteristics, tumor status, operation-related variables, and short- and long-term outcomes. Univariate analysis for repeat hepatectomy identified the following five prognostic risk factors: T factor （＞SE） of the primary cancer, number of tumors involved in the initial hepatectomy （＞5）, interval from first to second hepatectomy （＜1year）, number of tumors involved in second hepatectomy （＞3）, and post-operation time （＞30days）. By multivariate analysis, T factor （＞SE） of the primary cancer, number of tumors in the initial hepatectomy （＞5）, and number of tumors in the second hepatectomy （＞3） were independently associated with a worse survival after surgery for CRLM. Although surgical outcomes of the third hepatectomy were not compared with those of the first and second hepatectomy, there were no obvious differences, nor did the 1-, 3-, and 5-year survival rates differ significantly among the three groups. Repeat hepatectomy for CRLM could improve long-term survival. In addition, patients undergoing a third hepatectomy showed a similar survival benefit to those having one or two resections

Fast-track Surgery Protocol for Hepatectomy and the Rate of Surgical Site Infections: A Single-center Study

The fast-track surgery protocol, including perioperative immunonutritional management, is increasingly gaining attention for the prevention of surgical site infections （SSIs）. To analyze the association between the fast-track surgery protocol employed at a single center and outcomes, including SSIs and the length of hospital stays. This retrospective analysis included 217 patients who underwent hepatectomy at the study department between January 2009 and February 2014. Patients were divided into two groups: those managed by a conventional protocol （group C, n＝75） and those managed by the fast-track surgery protocol （group F, n＝142）. There were no significant differences in patient characteristics or factors between the two groups. However, serum albumin and total cholesterol levels before surgery were significantly higher in group F than in group C, and pre-hepatectomy C-reactive protein （CRP） levels were lower in group F than in group C. Moreover, serum albumin and CRP levels at postoperative day 7 were better in group F than in group C. The operations were longer in group F than in group C （312 vs. 286 min） and blood loss volume was less （385 g in group F vs. 428 g in group C）. SSI rates were significantly lower in group F （4.2％, n＝6） than in group C （13.3％, n＝10）, and the length of hospital stay was significantly shorter in group F （16.7 days） than in group C （25.8 days）. The fast-track surgery protocol as a perioperative management strategy may improve preoperative nutritional status and postoperative inflammation, with subsequent reductions in SSI rates and the length of hospital stay in patients undergoing hepatectomy

Evaluation of Surgical Stress Associated with Video-assisted Thoracic Surgery for Esophageal Cancer According to Interleukin-6 Variation in Pleural Cavity Lavage Fluid

Esophagectomy for esophageal cancer is one of the most invasive gastrointestinal surgeries. In 1996, we introduced video-assisted thoracic surgery for esophageal cancer (VATS-E) to reduce surgical stress. In 2010, we started employing artificial pneumothorax (AP) using carbon dioxide gas in VATS-E to further reduce surgical stress. In this study, we evaluated interleukin-6 (IL-6) levels in pleural cavity lavage fluid (PLF) of patients undergoing VATS-E with or without AP, and examined the effect of AP on VATS-E-induced stress. This non-randomized study included patients who underwent VATS-E with or without AP at Showa University Hospital between 2009 and 2013 and from whom PLF could be collected. IL-6 concentrations in PLF were examined before and after the thoracic part of the operation. We compared IL-6 variation, defined as the difference between IL-6 concentrations in PLF before and after the thoracic part of the operation, between patients for whom AP was used and those for whom it was not used. A total of 52 patients were included in the study; 26 underwent VATS-E with AP (group AP), and 26 underwent VATS-E without AP (group NP). IL-6 concentrations in PLF were significantly elevated immediately after the thoracic part of the operation in both groups. IL-6 variation in PLF correlated with both thoracic operative time and blood loss, which were considered practical parameters of surgical stress, and was significantly lower in group AP than in group NP. In conclusion, IL-6 variation in PLF is a useful and sensitive maker of surgical stress during VATS-E. VATS-E with AP is less invasive than VATS-E without AP because AP lowers the perioperative systemic inflammatory response to thoracic surgery

Feasibility of Precoagulation Without the Pringle Maneuver for Endoscopic Hepatectomy of Cirrhotic Liver

Various methods, devices, and techniques have been developed to improve safety during laparoscopic hepatectomy procedures. Among these, the Pringle maneuver （PM） is widely used to minimize blood loss during liver transections; however, the risk of ischemic injury associated with this technique is increased by poor hepatic reserve and regeneration dysfunction secondary to liver cirrhosis. This retrospective study evaluated the short-term outcomes and feasibility of precoagulation for endoscopic hepatectomy without PM in patients with liver cirrhosis. Eleven patients with liver cirrhosis who also underwent endoscopic hepatectomy for hepatocellular carcinoma were recruited to undergo either microwave tissue coagulation or radiofrequency ablation for precoagulation before liver transection. A wedge resection without the PM was performed in all patients, with seven patients selected for bipolar radiofrequency ablation and four patients for microwave coagulation therapy. The procedures included video-assisted thoracoscopic hepatectomy in two patients and laparoscopic hepatectomy in nine patients. One patient who underwent radiofrequency ablation developed postoperative bleeding （Clavien-Dindo grade Ⅲ）. In conclusion, precoagulation can help to minimize intraoperative blood loss without the PM, contributing to effective resection of liver tumors. We propose that precoagulation could serve as a standard technique for endoscopic hepatectomy in patients with cirrhosis