A Consumer-Based Model of Competitive Diffusion of Two Goods: The Effects of Network Externalities and Local Interactions

The diffusion of two competitive, interchangeable, and durable goods is studied under the framework of a spatial game where consumers are distributed on a two-dimensional square lattice and play 3$\times$3 symmetric coordination-like games with their nearest neighbors. There are three strategies, either consuming a product A or B, or a strategy C of not consuming either A or B. The payoff matrix of the game contains the positive effects of network externality, that is, the payoffs are increasing functions of the number of agents adopting the strategies A or B. Both simulations and mean-field approximation show that the existence of the positive effects of the network externality amplifies any slight initial difference in the number of agents who adopt either A or B and eventually promotes the superior product to take over the entire market. On the other hand, without effects of the network externality the slight initial difference is not enlarged and both superior and inferior products are observed to coexist by forming clusters in the market. Moreover, the effects of innovation factors that help an inferior product to retake the market are studied. It is shown that both the timing and size of the innovation factor matter for an inferior product in order to retake the market.competitive diffusion, network externality, local interaction, global externality, local externality, evolutionary game, spatial game

Colon Hypoperfusion After Artery Ligation

Background: Anastomotic leakage (AL) after colorectal surgery is associated with insufficient vascular perfusion of the anastomotic ends. This study aimed to evaluate the effect of high vs. low ligation of the ileocolic artery and inferior mesenteric artery, respectively, on the vascular perfusion of the bowel stumps during ileocecal resection (ICR) and anterior rectal resection (AR). Methods: We retrospectively evaluated patients who underwent ICR or AR between 2016 and 2020. Real-time indocyanine green fluorescence angiography was performed to measure the fluorescence time (FT) as a marker of the blood flow in the proximal and distal stumps before anastomosis. Results: Thirty-four patients with lower right-sided colon cancer underwent laparoscopic ICR. Forty-one patients with rectosigmoid colon or rectal cancer underwent robotic high AR (HAR) (n = 8), robotic low AR (LAR) (n = 6), laparoscopic HAR (n = 8), or laparoscopic LAR (n = 19). The FT was similar in the ileal and ascending colon stumps (p = 1.000) and did not differ significantly between high vs. low ligation of the ileocolic artery (p = 0.934). The FT was similar in the sigmoid colon and rectal stumps (p = 0.642), but high inferior mesenteric artery ligation significantly prolonged FT in the sigmoid colon during AR compared with low ligation (p = 0.004), indicating that the high ligation approach caused significant hypoperfusion compared with low ligation. The AL rate was similar after low vs. high ligation. Conclusions: Low vascular perfusion of the bowel stumps may not be an absolute risk factor for AL. High inferior mesenteric artery ligation could induce sigmoid colon stump hypoperfusion during anterior rectal resection

日本の伝統的な漢方薬である大建中湯は推進性の運動パターンを誘導することにより結腸輸送を促進する

Background: The traditional Japanese herbal medicine, daikenchuto (DKT), has been used to treat constipation and postoperative ileus. However, the precise mechanisms involved in the pharmacological effects of DKT remain uncertain. The aim of this study was to clarify the effect of DKT on motor patterns and transit activity in the isolated rat colon. Methods: The entire colon or segments of the proximal colon in rats were isolated and placed in Krebs solution. The motility of the colon was evaluated by analyzing spatiotemporal maps of diameter derived from video imaging and measuring the intraluminal pressure in the anal end of the proximal colon, and the transit time of a plastic bead through the entire isolated colon. Key Results: Several types of propagating contractions were observed in the isolated entire colon. When DKT was added to Krebs solution, the frequency of large‐extent anal propagating contractions increased. DKT treatment increased the intraluminal pressure in the isolated proximal colon, which was related to the propagating contractions. This effect was abolished by treatment with the neural blocker tetrodotoxin. These findings suggest DKT induced peristaltic contractions in the isolated colon. DKT accelerated colonic transit activity, which was related to peristaltic contractions induction in the colon. These effects were also observed in the colons treated with bethanechol and the active ingredient of DKT, hydroxy‐α‐sanshool. Conclusions and Inferences: Daikenchuto could enhance colonic transit activity by inducing peristaltic contractions, which may be mediated by the activation of the enteric nervous system in the colon

Incision and suture to maintain motility

Background : Heineke-Mikulicz (HM) strictureplasty is commonly used to treat short stenoses in Crohn’s disease. However, the degree to which intestinal motility is maintained remains unclear. We compared the peristalsis and transport capacity of the sutured intestines with HM configuration and transverse (TS) and longitudinal (LS) incisions. Methods : The intestinal diameter, intraluminal pressure, and bead transit time of each sutured group were compared with that of the non-treatment (NT) group in the isolated proximal colon of rats. Propulsive contractions were induced using hydroxy-α-sanshool (HAS), a constituent of Japanese pepper. Results : There was no change in the intestinal diameter between HM, TS, and NT groups ; however, it was significantly narrowed at the suture site and its distal side in the LS group. After HAS administration, the intestinal diameter at the suture site in the HM group was higher than that in the LS group. The intraluminal pressure was higher and the transit time was shorter in the HM group compared to those in the LS group. Conclusions : The HM configuration, which widens the incision site and distal diameter and shortens the cut surface of the circular muscle in the longitudinal direction, may help maintain basal and HAS-induced intestinal peristalsis and motility

Intestinal hypoperfusion in patients with Crohn's disease revealed by intraoperative indocyanine green fluorescence imaging

Background: Anastomotic leakage has been reported as an independent risk factor for surgical recurrence at the anastomotic site in patients with Crohn's disease. An inadequate blood supply may contribute to this leakage. Real-time indocyanine green angiography has been useful for confirming vascular perfusion of the intestines. The aim of this study was to evaluate the use of intraoperative indocyanine green angiography to detect vascular perfusion of the intestines during ileocaecal resection in patients with Crohn's disease and colon cancer. Materials and methods: We retrospectively evaluated the medical records of 26 consecutive patients with colon cancer arising in the caecum or ascending colon and 3 consecutive patients with Crohn's disease without a history of disease-related surgery. The patients in the 2 cohorts had undergone ileocaecal resection at Tokushima University Hospital between January 2018 and January 2021. After ileocaecal resection, blood flow was evaluated in ileal (oral) and colon (anal) stapled stumps by indocyanine green fluorescence angiography. The fluorescence time was defined as the time from indocyanine green injection and flush of the injection route to the point when the stump showed the strongest fluorescent signal in the monitor. Results: The fluorescence time for the ileal and colon stumps in patients with Crohn's disease was 43.3 ± 8.8 s each and was significantly longer than the fluorescence time in the patients with colon cancer (29.4 ± 6.5 s and 29.6 ± 6.8 s, respectively) (P < 0.05). Conclusion: Intraoperative indocyanine green fluorescence imaging is safe and reproducible for assessing intestinal perfusion prior to anastomosis in patients with colon cancer and Crohn's disease

Daikenchuto accelerates the recovery from prolonged postoperative ileus after open abdominal surgery : a subgroup analysis of three randomized controlled trials

Purpose Prolonged postoperative ileus (POI) is a common complication after open abdominal surgery (OAS). Daikenchuto (DKT), a traditional Japanese medicine that peripherally stimulates the neurogenic pathway, is used to treat prolonged POI in Japan. To analyze whether DKT accelerates the recovery from prolonged POI after OAS, we conducted a secondary analysis of three multicenter randomized controlled trials (RCTs). Methods A secondary analysis of the three RCTs supported by the Japanese Foundation for Multidisciplinary Treatment of Cancer (project numbers 39-0902, 40-1001, 42-1002) assessing the effect of DKT on prolonged POI in patients who had undergone OAS for colon, liver, or gastric cancer was performed. The subgroup included 410 patients with no bowel movement (BM) before the first diet, a DKT group (n = 214), and a placebo group (n = 196). Patients received either 5 g DKT or a placebo orally, three times a day. The primary endpoint was defined as the time from the end of surgery to the first bowel movement (FBM). A sensitivity analysis was also performed on the age, body mass index and dosage as subgroup analyses. Results The primary endpoint was significantly accelerated in the DKT group compared with the placebo group (p = 0.004; hazard ratio 1.337). The median time to the FBM was 113.8 h in the placebo group and 99.1 h in the DKT treatment group. Conclusions The subgroup analysis showed that DKT significantly accelerated the recovery from prolonged POI following OAS

GIS オ カツヨウ シタ ノウカ ノ リノウ ヨウイン ブンセキ / ホッカイドウ カミカワ チイキ オ ジレイ ト シテ

1993年のコメ部分輸入自由化の開始,1998年の「食料・農業・農村基本法」の制定等近年にかけて我が国の農業を取り巻く環境は大きく変化してきている。かかる環境変化の中で我が国の農家数は急激に減少してきている。本研究では,農家の離農要因を農業経営的要因と地形的要因から分析する。分析対象地域は北海道の代表的な稲作地帯である上川地域である。従来の農業経営研究では地形的要因を離農要因として分析するためには実態調査に頼らなければ不可能だった。本研究では,農業集落地図と集落カードおよび国土地理院の数値地図のデータベースを作成し,このデータベースにGIS(地理情報システム)を適用することにより,広域な地域で離農の地形的要因を分析することが可能となった。本研究で得られた結論は次の2つである。北海道上川地区においては,1.1985年ごろまでは離農要因として傾斜や標高等の地形的要因が重要であったこと。2.1990年以降は経営耕地面積や農業労働力構成等農業経営的要因が重要になったこと。The situation of Japanese agriculture has been changing since the partial liberalization of the rice market in 1993 and the enactment of the new agricultural law in 1998. Under the current agricultural situation, the number of Japanese farm households has been declining rapidly. This paper analyzes reasons why farm households exit farming based on agricultural management factors and geographical factors. The analysis focuses on Kamikawa rice production area in Hokkaido. The usual agricultural management studies do not enable us to analyze the geographical factors of farm exit without an actual survey. In this paper, we analyzed the geographical factors of farm exit over a wide area by using Geographic Information System (GIS) and a database. The database consists of agricultural census data and additional information that are location-specific. Some of our conclusions regarding this particular case are as follows. 1. Until around 1985, important factors of farm exit were geographical ones such as a slope and height above sea level. 2. Since 1990, important factors of farm exit have been agricultural management factors such as agricultural land and agricultural labor force composition

Long-term survival with RAS-associated autoimmune leukoproliferative disorder with somatic KRAS mutation:A case report

　RAS -associated autoimmune leukoproliferative disorder (RALD) is a recently reported rare nonmalignant autoimmune disorder. The characteristic clinical findings of RALD include monocytosis, leukocytosis, lymphoproliferation, and autoimmune phenomena. RALD is defined by somatic mutations in KRAS or NRAS . It is a new disease that was reported by Niemela and Takagi in 2011. The prognosis and incidence are currently unknown and the treatment strategy has not yet been established.　Here we describe the long-term survival of a patient with who displayed a somatic KRAS G12D mutation. His clinical features and labolatory data were overlapped with juvenile myelomonocytic leukemia and chronic myelomonocytic leukemia. Mercaptopurine hydrate, hydroxycarbamide and azacitizine were administered to control white blood cell count and improve clinical symptoms. He had a long survival time without hematopoietic stem cell transplantation