Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Isao Hirayama is active.

Publication


Featured researches published by Isao Hirayama.


Journal of The American College of Surgeons | 2002

Gum chewing enhances early recovery from postoperative ileus after laparoscopic colectomy.

Takayuki Asao; Hiroyuki Kuwano; Jun-ichi Nakamura; Nobuhiro Morinaga; Isao Hirayama; Munenori Ide

BACKGROUND Postoperative ileus limits early hospital discharge for patients who have undergone laparoscopic procedures. Sham feeding has been reported to enhance bowel motility. Here, the effect of gum chewing is evaluated as a convenient method to enhance postoperative recovery from ileus after laparoscopic colectomy. STUDY DESIGN A total of 19 patients who underwent elective laparoscopic colectomy for colorectal cancer participated in the study. Each patient was randomly assigned to one of two groups: a gum-chewing group (n = 10, mean age 58.6 years, range 50 to 71 years) or a control group (n = 9, mean age 60.6 years, range 45 to 80 years). The patients in the gum-chewing group chewed gum three times a day from the first postoperative AM until oral intake. The times of the first passage of flatus and defecation were recorded precisely. RESULTS The first passage of flatus was seen, on average, on postoperative day 2.1 in the gum-chewing group and on day 3.2 in the control group (p < 0.01). The first defecation was 2.7 days sooner in the gum-chewing group (postoperative day 3.1) than in the control group (5.8 days; p< 0.01). All patients tolerated gum chewing on the first operative AM. The postoperative hospital stays for the gum-chewing and control groups were 13.5+/-3.0 days and 14.5+/-6.1 days, respectively. CONCLUSIONS Gum chewing aids early recovery from postoperative ileus and is an inexpensive and physiologic method for stimulating bowel motility. Gum chewing should be added as an adjunct treatment in postoperative care because it might contribute to shorter hospital stays.


Surgery Today | 2000

Lymphoepithelial Cyst of the Pancreas: Report of a Case

Akihito Idetsu; Hitoshi Ojima; Kana Saito; Isao Hirayama; Yasuo Hosouchi; Yasuji Nishida; Takashi Nakajima; Hiroyuki Kuwano

A lymphoepithelial cyst (LEC) is an extremely rare benign lesion of the pancreas. During a medical check-up, a 77-year-old man without any symptoms was found to have a cyst in the body of the pancreas. His serum carbohydrate antigen 19-9 level was slightly elevated. Computed tomography showed a multilocular, low-attenuating cyst on the superior surface of the pancreatic body. Thus, we performed distal pancreatectomy with splenectomy. Histological examination revealed that the cyst wall was lined with squamous epithelium and surrounded by abundant mature lymphoid tissue. Keratinous substances were present in the cyst. An LEC of the pancreas is associated with a good prognosis and, although unusual, it should be considered in the differential diagnosis of pancreatic cystic lesions. Minimal resection of the cyst should be performed whenever possible, and extensive surgery avoided. For patients with a high surgical risk, fine-needle aspiration biopsy may be considered.


Mammalian Genome | 2006

Chromosome 2 locus Nidd5 has a potent effect on adiposity in the TSOD mouse.

Shin Mizutani; Hiroshi Gomi; Isao Hirayama; Tetsuro Izumi

We previously reported a quantitative trait locus for body weight, non-insulin-dependent diabetes 5 (Nidd5), on Chromosome 2 in the TSOD (Tsumura, Suzuki, Obese Diabetes) mouse, a model of polygenic obese type 2 diabetes. To find the gene responsible for a specific component of the pathogenesis, we used a marker-assisted selection protocol to produce congenic strains. These mice are designed to carry a control BALB/cA-derived genomic interval and a TSOD background to look for loss of phenotype. One of the strains with the widest congenic interval, D2Mit297-D2Mit304, showed reductions in both body weight and adiposity compared with TSOD mice. The phenotypic analyses of other congenic strains further narrowed the locus in a 9.4-Mb interval between D2Mit433 and D2Mit91, around which numerous loci for body weight and adiposity have been mapped previously. Although the locus showed a relatively modest effect on body weight, it had a major influence on fat mass that explains approximately 60% of the difference in the adipose index between parental TSOD and BALB/cA mice. Furthermore, the congenic strain with a minimal BALB/cA-derived region showed significantly smaller cell sizes of white and brown adipocytes compared with the control littermates. However, the locus did not primarily affect food consumption, general activity, or rectal temperature after cold exposure, although there are clear differences in these traits between the parental strains. The present work physically delineates the major locus for adiposity in the TSOD mouse.


Clinical Radiology | 2003

Spasmolytic Effect of Peppermint Oil in Barium During Double-contrast Barium Enema Compared with Buscopan

Takayuki Asao; Hiroyuki Kuwano; Munenori Ide; Isao Hirayama; Jun-ichi Nakamura; Koichiro Fujita; R Horiuti

AIM To evaluate the efficacy of peppermint oil in barium as a spasmolytic agent during a double-contrast barium enema (DCBE). MATERIALS AND METHODS A total of 383 DCBEs with positive results from occult blood tests were assessed. Patients were assigned to one of four groups: peppermint in barium (n=91), peppermint in tube (n=90), Buscopan (n=105), or no treatment (n=97). After a screening sigmoidoscopy, the DCBEs were performed using air as a distending gas. In the Buscopan group, the DCBE was performed with an intramuscular injection of 20mg Buscopan at the start of the examination. Patients in the no-treatment group underwent DCBE without any spasmolytic agent. A peppermint oil preparation (30ml) was mixed in the barium solution for patients in the peppermint-in-barium group, and the same dose of peppermint oil was included in the enema tube in the peppermint-in-tube group. The presence of spasm on a series of spot films was evaluated without information about the type of spasmolytic agent used. RESULTS The percentage of patients in the four groups (no treatment, Buscopan, peppermint in tube, and peppermint in barium) with absence of spasm in the entire colon on the series of spot films was 13.4, 38.1, 41.8, and 37.8%, respectively. In the group using peppermint oil or Buscopan, the rate of patients with non-spasm examination was higher than that in no-treatment group (p<0.0005). Peppermint oil had the same spasmolytic effect as the systemic administration of Buscopan in the transverse and descending colon. Peppermint oil had a stronger effect in the caecum and the ascending colon than a Buscopan injection (p<0.005). There was no advantage to placing peppermint oil in the enema tube over mixing it in the barium solution. A total of 157 polyps were found during the DCBE procedures, and no differences were observed in the number of lesions among the four groups. Peppermint oil did not impair image quality. CONCLUSION Barium solution mixed with peppermint oil was safe and effective for the elimination of colonic spasm during the DCBE procedure, and it could be used instead of Buscopan.


World Journal of Surgery | 2006

Factors Predicting Long-term Responses to Splenctomy in Patients with Idiopathic Thrombocytopenic Purpura

Hitoshi Ojima; Toshihide Kato; Kenichirou Araki; Kaori Okamura; Ryokuhei Manda; Isao Hirayama; Yasuo Hosouchi; Yasuji Nishida; Hiroyuki Kuwano

BackgroundIdiopathic thrombocytopenic purpura (ITP) is an autoimmune disorder for which appropriate diagnostic treatments are uncertain. The response to splenectomy varies from 60% to 90%, and the remaining patients relapse and require further treatment. Therefore, it is important to predict the outcome of splenectomy before and after surgery. The objective of this study was to evaluate the efficacy of splenectomy in patients diagnosed with ITP.Materials and MethodsFrom 1988 to 2004, we splenectomized 32 patients with ITP; 17 underwent laparoscopic splenectomy (LS) and 15 underwent conventional open splenectomy (OS). For analysis, patients were separated retrospectively into two groups: the “responding group,” those who showed good outcomes with splenectomy, and the “non-responding group,” those who did not show good outcomes with splenectomy. Blood samples were examined before and immediately after surgery (day 0) and on postoperative days (POD) 1, 3, 5, and 7.ResultsThe median follow-up was 8.3 years (range: 1–16 years). The overall 5- and 10-year survival rates after splenectomy were 96.9% (one death). The responding group included 24 patients (75%), and the non-responding group included 7 (21.9%). Platelet counts in the responding group increased gradually until POD 7, and although platelet counts in the non-responding group were almost constant until POD 5, they subsequently decreased until POD 7. Average platelet counts in the responding and non-responding groups were 269 and 124 × 109/l on POD 7, respectively (P < 0.05). The pre- to post-surgery ratio of platelet counts were almost the same as the result of the actual data. Platelet counts during the long-term follow-up for the responding and non-responding groups were related to those noted on discharge.ConclusionsA high platelet count on POD 7 was associated with a good response to splenectomy, but age at surgery, the time interval between diagnosis and splenectomy, and prior responses to corticosteroid were not. We suggest that long-term outcomes of splenectomy can easily be predicted by platelet counts on POD 7.


Oncology | 2004

Cell Density Modulates the Metastatic Aggressiveness of a Mouse Colon Cancer Cell Line, Colon 26

Hiroyuki Kuwano; Tatsuya Miyazaki; Soichi Tsutsumi; Isao Hirayama; Tatsuo Shimura; Erito Mochiki; Kenichi Nomoto; Minoru Fukuchi; Hiroyuki Kato; Takayuki Asao

Objective: Although cell density in cultured cells has demonstrated several alterations in the nature of cell kinetics, the changes in the metastatic aggressiveness of cancer lines under different cell densities have not yet been studied. Methods: In the current study, we investigated the influence of changing the cell density of cultured cancer cells (colon 26 and B16-F10) injected into the tail vein in BALB/c mice on the metastatic activity by evaluating the number of lung metastases, and the possible mechanisms of this phenomenon were discussed based on the basis of the results of an invasion assay and a cell adhesion assay. Results: The number of metastatic nodules was significantly higher in the high-density group than in the low one in colon 26 (p < 0.005), however, this phenomenon was not seen in B16-F10. Next, we performed the same experiment by changing the environment to the opposite conditions for the cells in the low- and high-density groups, and the results showed the metastatic activities to be always higher in the high-density group. Moreover, although no difference was seen regarding the invasive activity between the high- and low-density groups, an adhesion assay showed the difference in the adhesion cell rate to be significantly higher in the high-density group especially in early period after coculture with human umbilical vein endothelial cells (HUVEC) (p < 0.05). Conclusion: In some cell types, the metastatic activity could be altered and reversed by changing the environment, such as the cell density, during a relatively short period. As a result, the epigenetic changes of cancer cells are thus suggested to play a certain role in the malignant potentiality.


Case Reports in Gastroenterology | 2011

An Individual with Gastric Schwannoma with Pathologically Malignant Potential Surviving Two Years after Laparoscopy-Assisted Partial Gastrectomy

Akira Watanabe; Hitoshi Ojima; Shigemasa Suzuki; Yasushi Mochida; Isao Hirayama; Yasuo Hosouchi; Yasuji Nishida; Kenji Kashiwabara; Tetsuro Ohno; Erito Mochiki; Hiroyuki Kuwano

Schwannomas are a kind of neurogenic tumor. They are generally benign and originate primarily from the central and peripheral nerve. They rarely develop in the gastrointestinal tract: gastric schwannomas make up 0.2% of gastric neoplasms. A malignant gastric schwannoma is a comparatively rare tumor, a few cases have been reported until now. We present the case of a 34-year-old male patient diagnosed during medical examination. The patient was treated with surgical resection, and 2 years passed without recurrence.


Surgical Laparoscopy Endoscopy & Percutaneous Techniques | 2003

An easy and certain method to prevent dislodging of laparoscopic ports.

Takayuki Asao; Hiroyuki Kuwano; Tatsuo Shimura; Erito Mochiki; Makoto Suzuki; Isao Hirayama; Atsushi Takahashi

The dislodgement of a laparoscopic port during surgery is a common problem in patients with thin abdominal walls, especially children. In this paper, we report a new technique and a simple device to fix a laparoscopic port. The device consists of an O-ring and connecting threads that are tied to the ring at two points. The connecting thread is passed though the ports cannula, and a trocar is set in the cannula beforehand. The port with the inner trocar is placed into the abdominal cavity, and the trocar is removed. The ring is brought into the abdominal cavity with a laparoscopic forceps through the cannula. After the tip of the forceps has been passed through the ring in the abdominal cavity, the thread connected to the ring is withdrawn, and the ring is fixed on the cannula by anchoring the thread on the port extracorporeally. Such a device was used to fix a total of 95 ports during 12 laparoscopic colectomies, 7 gastrectomies, 19 cholecystectomies, 2 appendectomies, and 1 resection of Meckels diverticulum. Four children were among these cases. Not a single port slipped off, even in cases involving infants and obese patients. No complications relating to use of this device were observed. The new stabilizing device is simple, cost effective, and useful for prevention of the dislodging of various types of conventional ports, especially in the case of infants.


Surgical Endoscopy and Other Interventional Techniques | 2003

Intraoperative location of small gastrointestinal cancers with a handheld gamma probe.

Takayuki Asao; Hiroyuki Kuwano; Munenori Ide; Isao Hirayama; Jun-ichi Nakamura; Keigo Endo

The location of a small lesion must be precisely identified during laparoscopic surgery. A gamma probe that is usually used for navigating sentinel lymph nodes was evaluated for its usefulness in locating small gastrointestinal lesions (14 gastric and 10 colonic). A total of 2 mCi of a Tc99m-labeled rhenium colloid was injected endoscopically around a tumor 16 h prior to surgery. During operation, the abdominal cavity was scanned using a handheld gamma probe (Navigator GPS, Tyco HealthCare, Norwalk, CT, USA). In all cases, the injection site was identified as the highest spot in the abdominal cavity, with 2585 counts per second on average (range, 910–8800 counts per second). The highest count in a lymph node was 637 per second on average. The gamma probe is a useful tool for identifying small gastrointestinal lesions during open and laparoscopic operations.


Diabetes | 1999

Genetic analysis of obese diabetes in the TSOD mouse.

Isao Hirayama; Zhaohong Yi; Sumiko Izumi; Ichiro Arai; Wataru Suzuki; Yukio Nagamachi; Hiroyuki Kuwano; Toshiyuki Takeuchi; Tetsuro Izumi

Collaboration


Dive into the Isao Hirayama's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Erito Mochiki

Saitama Medical University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge