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Biomedical subjects

M Okajima

Publications and source records attributed to M Okajima.

At least 19 recordsLinked to original sources
PubMed2007

Rho-associated kinase inhibitor reduces tumor recurrence after liver transplantation in a rat hepatoma model.

Tumor recurrence after liver transplantation still remains a significant problem in patients with hepatocellular carcinoma. The small GTPase Rho/Rho-associated kinase (ROCK) pathway is involved in the motility and invasiveness of cancer cells. We investigated whether tacrolimus activated the Rho/ROCK signal pathway to promote the invasiveness of rat hepatocellular carcinoma cells. We also investigated whether the ROCK inhibitor Y-27632 suppressed tumor recurrence after experimental liver transplantation in a rat hepatocellular carcinoma model. Orthotopic liver transplantation was performed in hepatocellular carcinoma cell line McA-RH7777-bearing rats. Tacrolimus was administered to liver transplant rats and these rats were divided into two groups: the Y-27632-treated (10 mg/kg, for 28 days) group and the Y-27632-untreated group. Tacrolimus enhanced the cancer cell migration and stimulated phosphorylation of the myosin light chain (MLC), a downstream effector of Rho/ROCK signaling. Y-27632 suppressed the cancer cell migration and tacrolimus-induced MLC phosphorylation. Suppression of tumor recurrence after liver transplantation and significant prolongation of survival were observed in the Y-27632-treated rats in comparison with theY-27632-untreated rats. Tacrolimus stimulates the Rho/ROCK signal pathway to enhance the invasiveness of hepatocellular carcinoma, and the ROCK inhibitor Y-27632 can be used as a new antimetastatic agent for the prevention of tumor recurrence after liver transplantation.

Amides↗
PubMed2006

A groundbreaking new suturing device: the Excalibur.

BACKGROUND: Laparoscopic knot tying can be stressful. We reported two simple techniques, known as the Thumbs up! knot and the Tornado knot. We have further refined these procedures with the development of a new needle holder, called the Excalibur suturing needle holder. MATERIALS: This forceps differ from most conventional forceps in that the hinge is designed to stick out. The large hinge is stored out of the way when the forceps are closed, to prevent the thread accidentally catching. RESULTS: The thread is hooked on the projected hinge, which resembles the heel of a high-heel shoe. By using this forceps, the laparoscopic knot tying becomes easier for not only well experienced but also less experienced surgeons. CONCLUSIONS: The Excalibur, with its high heel, can complete knots with simple straight-line motion, making knot tying easier. This forceps will help reduce the stresses associated with intra-corporeal knot tying.

Equipment Design↗
PubMed2005

Multimedia article. The keys to the new laparoscopic world Thumbs up! knot and Tornado knot.

Most laparoscopic surgeons feel some anxiety when performing intracorporeal knotting with conventional techniques [1, 2]. Two factors contribute to this anxiety. The first is the necessity of recognizing three dimensions on a two-dimensional monitor. The conventional intracorporeal knotting techniques make loops by twisting the thread with a second pair of forceps. This necessitates cooperative movement of both hands, with the added difficulties of depth perception. Regular touch confirmations reduce problems with depth perception. However, touch confirmation is more complicated in laparoscopic surgery than in laparotomy. The second problem is that tied loops can come loose and escape the instruments, especially with hard thread. This is not only stressful but also increases operation time.

Humans↗
PubMed2001

Accumulation of beta-catenin protein and mutations in exon 3 of beta-catenin gene in gastrointestinal carcinoid tumor.

The molecular basis of carcinogenesis in gastrointestinal carcinoid tumors is not well understood. To clarify the contribution of the Wnt/beta-catenin signaling to this type of carcinogenesis, we investigated 72 cases of gastrointestinal carcinoid tumor both immunohistochemically and by direct sequencing of beta-catenin. Accumulation of beta-catenin in the cytoplasm and/or nucleus was observed in 57 cases (79.2%). We also detected mutations in exon 3 of beta-catenin in 27 cases (37.5%) and one mutation in APC (1.4%). Our results suggest that alterations in the Wnt/beta-catenin signaling pathway may be involved in the development of gastrointestinal carcinoid tumors.

Carcinoid Tumor↗
PubMed2001

Improvement of macromolecular clearance via lymph flow in hamster gingiva by low-power carbon dioxide laser-irradiation.

BACKGROUND AND OBJECTIVE: Although therapeutic effects of low-power laser-irradiation on periodontal disease have been reported, little is known about the biological effects of laser-irradiation in the gingiva. Recently we reported that topical warming stimulated macromolecular clearance via lymph flow in hamster gingiva. This study was conducted to investigate whether low-power laser-irradiation affects macromolecular clearance via the lymph flow in the gingiva. STUDY DESIGN/MATERIALS AND METHODS: We injected 14C-methylated albumin into the mandibular gingiva of anesthetized hamsters followed by topical carbon dioxide (CO2) laser-irradiation (30 seconds, 0.5-1.5 W). We measured the clearance of radiolabeled albumin from the gingiva and its drainage into submandibular lymph nodes during 10 minutes. RESULTS: The clearance of the radiolabeled albumin from the gingiva and the influx into the submandibular lymph nodes were increased by CO2 laser-irradiation. CONCLUSION: Low-power CO2 laser-irradiation improves macromolecular clearance via the lymph flow in hamster gingiva.

Albumins↗
PubMed2001

Duodenogastric reflux following cholecystectomy in the dog: role of antroduodenal motor function.

BACKGROUND: Duodenogastric reflux has been implicated in the pathogenesis of gastric ulcer and gastritis. Duodenogastric reflux after cholecystectomy is also a possible cause of post-cholecystectomy syndrome. AIM: To investigate the role of antroduodenal motor function in increased duodenogastric reflux following cholecystectomy and the effect of trimebutine maleate (trimebutine) on the duodenogastric reflux in conscious dogs. METHODS: Antropyloric and duodenal motility and bile acids content in the gastric juice were measured for 3 h during the inter-digestive state in dogs with or without cholecystectomy. RESULTS: Bile acids content in the gastric juice of cholecystectomized dogs was significantly higher than that of non-cholecystectomized dogs. The frequency of pyloric relaxation during phase II of the migrating motor complex was significantly increased following cholecystectomy. Intravenous infusion of trimebutine inhibited both the increased duodenogastric reflux and the frequency of pyloric relaxation in the cholecystectomized dog. CONCLUSION: Duodenogastric reflux and frequency of pyloric relaxations were increased in cholecystectomized dogs and trimebutine suppressed both of them. These findings suggest that the increased frequency of pyloric relaxation contributes to the duodenogastric reflux following cholecystectomy.

Animals↗
PubMed2001

Lactate dehydrogenase isozymes in and intralesional steroid injection therapy for pseudocyst of the auricle.

BACKGROUND: Various treatments for pseudocyst of the auricle have been reported. Recently, several patients have been treated successfully with steroid injections. The lactate dehydrogenase (LDH) levels of cystic fluid have been reported to be high, and the LDH-4 and LDH-5 isozymes were found to predominate, although the serum LDH levels and LDH isozyme patterns were normal. OBJECTIVE: To find a way of preventing auricular pseudocyst recurrences after steroid injection therapy and to examine the relationships between recurrences and the LDH level and isozyme pattern of the cystic fluid. METHODS: Steroid injection therapy was given to nine Japanese patients with pseudocyst of the auricle at our clinic between 1994 and 1999. We determined the LDH level and isozyme pattern of the cystic fluid and sera of seven patients. RESULTS: All nine patients in this series were treated successfully with steroid injections, although three suffered recurrences. Although the serum LDH levels of seven patients were almost normal, their cystic fluid LDH levels were very high. LDH-4 and LDH-5 predominated in the cystic fluid of all seven, although their serum LDH isozyme patterns were virtually normal. CONCLUSIONS: Auricular pseudocyst recurrences show no relationship with either the LDH levels or isozyme pattern. An undiluted solution of steroid fluid should be used in order to prevent recurrences.

Adult↗
PubMed2000

Study on eight patients with malignant tumors after renal transplantation.

The high incidence of cancer after renal transplantation is now a critical concern since the graft survival rate has been improved extensively. We experienced 9 malignancies in 8 patients out of 168 recipients up to December 31, 1999 in our hospital, consisting of a case of gastric plasmacytoma and cases of cancer in the liver (2), thyroid (2), prostate (1), breast (1), sigmoid colon (1) and gall-bladder (1). Two patients were diagnosed as having tumors within 3 months after transplantation, suggesting post-transplant acceleration of growth of the latent tumors. The other patients were diagnosed at an average of 128 months, ranging from 84 to 263 months after transplant. Two patients died of gastro-intestinal bleeding and acute heart failure. Four patients died directly of progressive neoplasm within 3 months after diagnosis. These results suggest that the course of malignancies developing in post-transplant recipients is more aggressive than that expected in non-transplant patients, and it is very important to intensively follow long-term surviving cases to detect the malignant tumors as early as possible.

Adolescent↗
PubMed2000

[A case report of unresectable colon cancer that disappeared following pharmacokinetic modulation chemotherapy (PMC)].

We encountered a case of unresectable colon cancer that disappeared following pharmacokinetic modulating chemotherapy (PMC). A 41-year-old male underwent ileotransverse anastomosis following a diagnosis of ileus due to unresectable colon cancer with peritoneal dissemination and multiple liver metastases. He was treated weekly with an intravenous infusion of 5-FU, 1,000 mg/body/24 hours and an oral administration of UFT 400 mg/day (PMC). After 6 months of weekly treatment of PMC, colon tumor disappeared and metastatic liver tumors decreased in size. PMC can be administered to outpatients without serious side effects; thus, this therapy improves the prognosis and the patient's quality of life.

Administration, Oral↗
PubMed1999

Basosquamous carcinoma after ultraviolet therapy with artificial sunlight.

We report a 63-year-old Japanese man with basosquamous carcinoma developing after ultraviolet therapy with artificial sunlight. Because he had had an eczematous lesion on the right leg five years previously, he had received ultraviolet therapy with artificial sunlight from a mercury-quartz lamp for a total of 30 sessions over a 3-year period. Physical examination revealed an irregular erythematous plaque measuring 5 x 6 cm, with slight eruptions and erosions, on the right leg. A brownish plaque, measuring 9 x 12 cm, surrounded the erythematous plaque. Histopathologically, in the nests of atypical cells in the dermis, nuclear palisading was present at the edge of each tumor cluster. Adjacent clusters exhibited transitions to squamous cells and contained horn pearls. Most of the cells of the epidermis and adnexa were atypical, but cells of the normal adnexal epithelium extended over the atypical cells of the epidermis in an umbrella-like fashion in other lesions. We believe that, in the present case, artificial sunlight therapy caused solar keratosis and that this developed into basosquamous carcinoma. To our knowledge, skin cancer developing after ultraviolet therapy with artificial sunlight without PUVA has not previously been reported in the English literature.

Carcinoma, Basosquamous↗
PubMed1998

Motility of the canine pyloric ring following a pylorus-preserving pancreatoduodenectomy.

Recently, function-preserving operations have become popular, and pylorus-preserving pancreatoduodenectomy (PPPD) is frequently performed for diseases of the head of the pancreas. However, there are only a few basic studies on the pyloric function after PPPD. Using strain gauge force transducers (SGTs), we studied the pyloric motility of normal and PPPD dogs. We prepared three normal and three PPPD dogs in which the SGTs were implanted onto the antrum and pyloric ring, etc. In conscious dogs, the spontaneous gastrointestinal motility was recorded, and the plasma motilin concentration was measured during the interdigestive state. Following the administration of exogenous Leu13-motilin, the motility was again recorded. The relaxation and opening of the pyloric ring was observed synchronously with intense contractions of the antrum during the phase III of normal dogs. Phase III-like motility was recorded in the PPPD dogs, which was not a typical periodic motility. The plasma motilin concentration of one PPPD dog could be measured, and the motilin levels during the phase III-like motility were higher than during phase I. The phase III-like motility was induced by Leu13-motilin in both normal and PPPD dogs. The phase III-like motility recorded in the PPPD dogs was not a typical periodic one, and this aberrant motility was considered to be one of the causes of delayed gastric emptying. Phase III-like motility was induced by the administration of Leu13-motilin; therefore, it is possible that Leu13-motilin improved the motility of the pyloric ring after PPPD.

Animals↗
PubMed1997

Inflammatory fibroid polyp of the ileum with the appearance of a Borrmann type II lesion, caused by colostomy irrigation: report of a case.

Inflammatory fibroid polyps (IFPs) are rarely found in the gastrointestinal tract. The majority of IFPs are sessile-pedunculated or pedunculated polypoid lesions, whereas a polyp presenting like a Borrmann type II lesion is extremely unusual. This report describes the case of a 74-year-old man with a history of intussusception, in whom a preoperative diagnosis of a cecal tumor of the ileocecal valve was made. A laparotomy subsequently revealed a lesion similar to a Borrmann type II tumor located 15 cm above the ileocecal valve, but not at the valve. The lesion was diagnosed as an IFP which had been caused by repeated colostomy irrigation. The aim of the present report is to draw attention to this entity, which should be included in the differential diagnosis of intussusception and small bowel obstruction.

Aged↗
PubMed1995

[Improvement of signal averaged electrocardiography--basic composition, performance and standard of the signal averaged ECG].

Useful electrocardiogram information is exist on the body surface in cases with low level cardiac signals' which are not identifiable with standard ECG techniques. Especially, His bundle potential and late potential were previously accessible only by invasive, catheter based methods. However, with the advancements in medical electronics device, signal averaged techniques with high gain low noise pre-amplifier and band pass filter, the record of body surface His bundle potential and late potential. The clinical study of Rozanski et al. and Simson demonstrated the relationship between late potential and ventricular tachycardia. Investigators are being made to standardize the technical approach. This papers reported basic composition and performance of signal averaged ECG and standard and features of body surface low level cardiac signals.

Animals↗
PubMed1995

[On time-frequency analysis at mid-QRS stage on body surface electrocardiogram].

The advanced technology in signal processing has been utilized for recording high resolution electrocardiogram. It has presented some new valuable informations, possibly reflecting electrical characteristics of myocardium. Detecting ventricular late potential is practical, however, it uses only part of high resolution signals, because of difficulty of dividing into higher frequency components. Therefore, high resolutional signals were analyzed using numerical filter in order to detect and verify higher frequency components at mid-QRS stage on body surface electrocardiogram. Precordial signals were summation-averaged and underwent narrow peak filtering using various peek frequencies increasing stepwisely between 50 Hz and 400 Hz. In conclusion, this minutely analyzing system was able to pick up valuable informations in mid-QRS stage signal. For example, harmonization of peek phases in several frequencies at QRS complex had gaps that suggested abnormality of local myocardium.

Arrhythmias, Cardiac↗
PubMed1995

[Multi-lead ambulatory electrocardiograph for recording body surface ST maps in daily life].

We attempted to construct ambulatory body surface isopotential maps of ST segment using our newly designed multi-lead ambulatory electrocardiograph. The multi-lead ambulatory electrocardiograph. The multi-lead ambulatory ECG system consisted of a commercially-available 4-channel recorder and a specially designed adapter, by which 30-lead ECGs were recorded together with body position signals for 24 hours. The electrode positions were selected from the 87 lead points for body surface mapping according to Yamada et al. Compensation for ST distortion and interpolation of ST level on time scale techniques were performed before the construction of ST maps. The extension and location of ST depression area thus obtained after compensation and interpolation were thought to be reasonable. In conclusion, the ambulatory recording of body surface ST maps is possible using our new device and may become useful for study of myocardial ischemia in daily life.

Body Surface Potential Mapping↗