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M Kitajima

Publications and source records attributed to M Kitajima.

At least 127 records · Page 7Linked to original sources
PubMed1999

Characterization of breast masses by dynamic enhanced MR imaging. A logistic regression analysis.

PURPOSE: To identify features useful for differentiation between malignant and benign breast neoplasms using multivariate analysis of findings by MR imaging. MATERIAL AND METHODS: In a retrospective analysis, 61 patients with 64 breast masses underwent MR imaging and the time-signal intensity curves for precontrast dynamic postcontrast images were quantitatively analyzed. Statistical analysis was performed using a logistic regression model, which was prospectively tested in another 34 patients with suspected breast masses. RESULTS: Univariate analysis revealed that the reliable indicators for malignancy were first the appearance of the tumor border, followed by the washout ratio, internal architecture after contrast enhancement, and peak time. The factors significantly associated with malignancy were irregular tumor border, followed by washout ratio, internal architecture, and peak time. For differentiation between benignity and malignancy, the maximum cut-off point was to be found between 0.47 and 0.51. In a prospective application of this model, 91% of the lesions were accurately discriminated as benign or malignant lesions. CONCLUSION: Combination of contrast-enhanced dynamic and postcontrast-enhanced MR imaging provided accurate data for the diagnosis of malignant neoplasms of the breast. The model had an accuracy of 91% (sensitivity 90%, specificity 93%).

Adult↗
PubMed1999

Dihydropyrimidine dehydrogenase activity and messenger RNA level may be related to the antitumor effect of 5-fluorouracil on human tumor xenografts in nude mice.

We investigated the correlation between tumor sensitivity to 5-fluorouracil (5-FU) and the enzymatic activity and mRNA levels of thymidylate synthetase (TS) and dihydropyrimidine dehydrogenase (DPD) using human tumor xenografts in nude mice. Three gastric carcinoma xenografts (SC-1-NU, St-4, and H-111), two colon carcinoma xenografts (Co-4 and Col-3-JCK), one pancreatic carcinoma xenograft (PAN-3-JCK), and one breast carcinoma xenograft (MX-1) were inoculated into nude mice. When the resultant tumors reached 100-300 mg, 5-FU was administered i.p. at a dose of 60 mg/kg in a schedule of three times every 4 days, and the antitumor activity of 5-FU was evaluated as the relative mean tumor weight in treated mice compared to control mice. Xenografts were also inoculated into untreated nude mice. When tumors weighed 200-300 mg, tumor tissues were resected for measurement of tumoral TS and DPD. TS and DPD activities were detected by the TS-binding assay and a radioenzymatic assay, respectively. mRNA levels were measured by semiquantitative reverse transcription-PCR, with glyceraldehyde-3-phosphate dehydrogenase coamplified as an internal standard. TS and DPD activities ranged from 84.7 to 775.5 fmol/mg protein and from not detectable to 79.7 pmol/min/mg protein, respectively. TS and DPD mRNA levels ranged from 0.51 to 9.90 and from not detectable to 0.93, respectively. The enzymatic activities of TS and DPD were correlated with observed mRNA levels. DPD levels were significantly correlated with 5-FU sensitivity, with high DPD activity and high DPD mRNA level resulting in low sensitivity to 5-FU. In contrast, no correlation between TS level and 5-FU sensitivity was observed. Tumoral DPD activity and DPD mRNA level may be useful indicators in predicting the antitumor activity of 5-FU.

Animals↗
PubMed1999

[Molecular alterations in Barrett's esophagus and adenocarcinoma].

Patients with Barrett's columnar-lined esophagus are at increased risk of developing esophageal adenocarcinoma, the incidence of which has increased rapidly especially in the USA. Although the number of patients with Barrett's adenocarcinoma is fewer in Japan than in the USA, all gastroenterologist should know its multistep carcinogenic process. Tumor suppressor genes (p53, p16), oncogenes (c-erbB-2, H-ras, K-ras, cyclin D1, src), and growth factor/receptor (TGF-alpha, EGFR) seem to cause the malignant transformation of Barrett's esophagus. Because detection of these molecular alterations is feasible, more accurate diagnosis of Barrett's esophageal biopsy specimens should be made by adding the molecular examination to the conventional pathologic examination.

Adenocarcinoma↗
PubMed1999

[Fusion of medicine and technology in endoscopic surgery].

Although endoscopic surgery has become widespread and is currently used in a wide range of general, thoracic, urologic, gynecologic, and orthopedic procedures, many major difficulties remain because sensorial information is restricted to a two-dimensional image, and effector instruments have limited maneuverability due to the rigid shaft axis fixed to the abdominal wall by the entry trocar. To overcome these problems, advanced engineering technology has been introduced in laparoscopic surgery which includes three-dimensional video imaging, robotic laparoscopic cameraholders, telemanipulated flexible effector instruments, and tactile feedback. A voice-controlled robotic laparoscopic holder (AESOP200, Computer Motion Inc. USA) provides stable support for the laparoscope during laparoscopic surgery performed by a single surgeon. A new computer-assisted telemanipulation robot (Intuitive Surgical Inc. USA) permits the performance of completely endoscopic coronary artery bypass and Nissen fundoplication. Furthermore, price reductions and technological advances in telecommunications have made telementoring in endoscopic surgery available for routine clinical use, and intercontinental surgical video teleconferences fruitful opportunities for discussing technical details. The fusion of medicine and technology in endoscopic surgery would overcome difficulties in the conventional endoscopic approach.

Humans↗
PubMed1999

[Pathophysiology and diagnosis of ischemic colitis].

Ischemic colitis is the most common manifestation of gastrointestinal ischemia. The presumed etiologies are numerous; however, it typically develops spontaneously. It is classified into the transient type, stricture type, and gangrenous type. The majority of patients with ischemic colitis, excluding the gangrenous type, follow a benign clinical course in the absence of major vasculature occlusion. It usually presents as an acute abdominal illness with bloody diarrhea. Diagnosis is confirmed by colonoscopy and/or barium enema. Nongangrenous ischemic colitis usually requires only conservative therapy, including repeated careful assessment, pain control, and fluid replacement, and is associated with a good prognosis. It may lead to the sequela of persistent segmental colitis or colonic strictures, occasionally requiring surgery. Urgent surgery and high morbidity and mortality rates are hallmarks of the gangrenous type. Special consideration must be given to those patients in whom ischemic colitis develops in the context of colon cancer or obstructive colonic lesions. Successful management of a patient with ischemic colitis requires a high degree of clinical suspicion, early diagnosis, careful follow-up, and prompt recognition of persistent disease.

Colitis, Ischemic↗
PubMed1999

Role of dipyridamole myocardial scintigraphy in abdominal aortic aneurysm repair.

BACKGROUND: We evaluated the usefulness of preoperative dipyridamole myocardial scintigraphy (DMS) under low-level exercise in predicting postoperative cardiac problems in patients undergoing elective abdominal aortic aneurysm (AAA) repair. METHODS EXPERIMENTAL DESIGN: retrospective comparison of patients who did and did not undergo the investigation preoperatively. SETTING: at the Keio University Hospital and the Kawasaki City Hospital. PATIENTS: eighty-five patients who had abdominal aortic aneurysm repair consecutively from 1986 to 1990 without undergoing dipyridamole myocardial scintigraphy preoperatively were compared with 118 patients who underwent the repair consecutively from 1991 to 1997 after having had preoperative scintigraphy. MEASUREMENTS: postoperative occurrences of myocardial infarction and angina pectoris in the two groups of patients were compared statistically. RESULTS: In the group not having scintigraphy, cardiac events occurred in 12 patients (14.1%) after repair. Ten patients had a myocardial infarction; six died within 30 days of operation and four died after the 31st postoperative day. The other two patients had angina pectoris; both survived. In the group having scintigraphy, there were no postoperative cardiac events (p<0.001). Seventeen patients had positive results on preoperative scintigraphy. Seven of them had undergone coronary artery bypass grafting and five coronary angioplasty before the repair. In the five other patients, scintigraphy, was found to have yielded false positive results. CONCLUSIONS: Dypiridamole myocardial scintigraphy is an accurate predictor of postoperative myocardial infarction and angina pectoris in patients being evaluated for elective abdominal aortic aneurysm repair and should be used routinely.

Aged↗
PubMed1999

Contrast enhancement of intracranial lesions: conventional T1-weighted spin-echo versus fast spin-echo MR imaging techniques.

BACKGROUND AND PURPOSE: The T1-weighted fast spin-echo (T1-FSE) MR imaging sequence is not used routinely, since the speed advantage is not as dramatic as it is in T2-weighted imaging. We evaluated the T1-FSE sequence to determine whether this technique can replace the conventional T1-weighted spin-echo (T1-SE) sequence for routine contrast-enhanced imaging. METHODS: Sixty-nine patients with intracranial enhancing lesions underwent both T1-SE and T1-FSE sequences in a random order after administration of contrast agent. Acquisition time was 55 seconds for the T1-FSE sequence and 2 minutes 38 seconds for the SE sequence. The conspicuity of enhancing lesions, peritumoral edema, and gray-to-white matter contrast as well as motion and flow artifacts were analyzed. Signal-to-noise ratios of enhancing lesions, gray matter, and white matter as well as contrast-to-noise ratios (CNRs) of enhancing lesions, with gray matter with white matter as the standard, were calculated. RESULTS: The conspicuity of enhancing lesions was better on T1-FSE sequences than on T1-SE sequences, although the difference in the CNRs of enhancing lesions did not reach significance. Images obtained with the T1-FSE sequence showed less flow and motion artifacts than did those obtained with the T1-SE sequence. The conspicuity of peritumoral edema and gray-to-white matter contrast was lower on the T1-FSE images than on the T1-SE images. CONCLUSION: The T1-FSE sequence reduces imaging time and has the potential to replace the conventional T1-SE sequence for the evaluation of enhancing lesions in the brain when time is a consideration.

Adolescent↗
PubMed1999

[Recent clinical trials for sepsis: analysis of the results and future perspectives].

Recent clinical trials with experimental immunotherapeutic agents for sepsis have not proven their overall benefit yet although some studies suggested significant effect of these antisepsis therapies. This review article summarizes the results of these trials, their analysis, lessons learned from past failure, and future perspectives for immunotherapies as anti-sepsis treatments.

Animals↗
PubMed1999

[Molecular biology in gastric cancer].

In gastric cancer, the process of carcinogenesis is thought to occur as a stepwise accumulation of genetic abnormalities. However, the mechanisms of the process of multistage carcinogenesis is still unknown for gastric cancer. Gene abnormalities seen in gastric cancer, including ras, myc, c-erbB-2, met, K-sam and cript are summarized herein. Abnormalities of cancer suppressor genes, including p53, RB and APC are also described. In our studies, the biological malignancy of patients with c-erbB-2 amplification was higher than that of patients without amplification. Moreover, the cases with amplification of c-erbB-2 were found to be highly correlated with distant organ metastasis. However, very little is currently known of the molecular abnormalities leading to gastric cancer. In order to clarify the multiple gene abnormalities in gastric cancer, we used the method of restriction landmark genomic scanning (RLGS). RLGS provides a useful method for genomic analysis of gastric cancer. In the future, new analytical methods that will permit screening of all gene abnormalities at once promise to improve our understanding of the mechanisms of gastric cancer.

Genes, erbB-2↗
PubMed1999

[Laparoscopic bowel resection for early colon cancer].

Following the successful introduction of laparoscopic cholecystectomy, many reports confirming the feasibility of using laparoscopy for bowel resection and predicting that it would be advantageous in terms of its minimal invasiveness have been published. In the context of cancer treatment, however, the feasibility of lymphadenectomy, the risk of recurrence, and survival have emerged as major concerns. Even though mucosal cancer (Tis) can be treated by endoscopic resection (ER), when this is not possible open surgery (OS) must be performed. In patients with T1 cancer, tumors showing slight submucosal layer invasion (sm 1) can be treated in the same way as Tis (in cancer) cancers. But 5% to 10% of patients with T1 cancer have massive submucosal layer invasion (sm 2-3) with paracolic lymph node metastasis. At least partial bowel resection with paracolic lymphadenectomy is considered necessary for T1 (sm 2-3) cancers in principle. In summary, laparoscopic local excision of Tis cancers that are endoscopically unresectable and laparoscopically assisted partial resection with paracolic lymphadenectomy for T1 cancers have become accepted because local excision and partial resection with paracolic lymphnedectomy are fairly simple to perform laparoscopically. Therefore as a strategy for the treatment of early colorectal cancer (CRC), minimally invasive laparoscopic bowel resection (LBR) has been positioned between endoscopic resection (ER) and open surgery (OS). While the difficulty of performing radical lymphadenectomy is considered one of the greatest obstacles to the introduction of laparoscopic bowel resection (LBR) for the treatment of advanced colorectal cancer (CRC), early colon cancer is a good indication for laparoscopic bowel resection.

Colonic Neoplasms↗
PubMed1999

[CA15-3].

Explore the source record for details and available documents.

Biomarkers, Tumor↗
PubMed1999

Laparoscopically assisted bowel resection for primary mucosa-associated lymphoid tissue lymphoma of the cecum.

We present the first report of laparoscopic resection for colorectal mucosa-associated lymphoid tissue (MALT) lymphoma. A 76-year-old man was found to have MALT lymphoma of the cecum during colonoscopy. He underwent a laparoscopically assisted ileocecal resection after admission and was discharged 9 days postoperatively without any complications. Colorectal MALT lymphoma is a rare neoplasm that responds favorably to locally directed therapy, because it tends to remain localized for prolonged periods. Laparoscopic surgery for colorectal MALT lymphoma is considered feasible because it is minimally invasive, making it suitable for treatment of low-grade malignancies, such as MALT lymphoma, which cannot be removed endoscopically.

Aged↗
PubMed1998

Molecular cloning and characterization of a novel human classic cadherin homologous with mouse muscle cadherin.

We used a novel cDNA cloning method based on the cadherin-beta-catenin protein interaction and identified a new human classic-type cadherin, which we named cadherin-15, from adult brain and skeletal muscle cDNA libraries. Sequence analysis revealed that this cadherin was closely related to mouse muscle cadherin and seemed to be its human counterpart. However, its deduced amino acid sequence differed from that of mouse muscle cadherin in that it had an extra 31-amino acid sequence at its C terminus that has been found neither in mouse muscle cadherin nor in any other known classic cadherin. Analysis of cadherin-15 protein expressed in L fibroblasts showed that it was cleaved proteolytically, expressed on the cell surfaces as a mature form of about 124-kDa, and functioned as a cell-cell adhesion molecule in a homophilic and specific manner, but Ca2+ did not protect it against degradation by trypsin. Our findings also suggest that cadherin-15 mediates cell-cell adhesion with a binding strength comparable to that of E-cadherin.

Adult↗
PubMed1998

Magnetic resonance imaging of esophageal squamous cell carcinoma using magnetite particles coated with anti-epidermal growth factor receptor antibody.

A highly specific and effective magnetic resonance imaging (MRI) contrast agent was prepared by coating super-paramagnetite particles with monoclonal antibodies (MAbs) directed against epidermal growth factor receptors (EGFRs), which are over-expressed in esophageal squamous cell carcinoma. The preparation maintained both the immunoreactivity of the MAbs and the full relaxing capability of the magnetite particles. The particles of this EGFR-specific contrast agent are 13.2 +/- 1.9 nm in size, and thus, it is assumed that they are smaller than capillary pores and, hence, able to escape scavenging by reticulo-endothelial system cells. The EGFR-specific T2-relaxing ability of this contrast agent was ascertained first in vitro, using the EGFR-expressing cell line TE8 and the EGFR-deficient cell line H69. The results in athymic rats bearing TE8 or H69 tumors revealed that the agent has EGFR-specific MRI contrast capacity in vivo. The electron-microscopic findings in TE8 tumor-bearing rats revealed that the magnetite particles had been taken up by their lysosomes. In conclusion, immuno-specific MRI using magnetite particles coated with MAbs against EGFR appears to be useful in the diagnosis of squamous cell carcinoma of the esophagus.

Animals↗
PubMed1998

Selective antitumor activity of MKT-077, a delocalized lipophilic cation, on normal cells and cancer cells in vitro.

BACKGROUND AND OBJECTIVES: 1-Ethyl-2-¿[3-ethyl-5-(3-methylbenzothiazolin-2-yliden)]-4-+ ++oxothiazolidin-2-ylidenemethyl¿pyridium chloride (MKT-077, formerly known as FJ776), a delocalized lipophilic cation, is known to accumulate in the mitochondria, according to the negative potential inside the mitochondria, and exert its cytotoxicity. METHODS: The single-cell suspensions of human cancer cell lines, human spleen cells, and fresh cancer specimens obtained from patients with gastric carcinoma were used for the 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-2H tetrazolium bromide (MTT) assay. RESULTS: The antitumor activity of MKT-077 was dose and concentration related, and 50% inhibitory concentrations (IC50) ranged from 1.7 to 14.3 microg/ml, with a mean +/- standard deviation (SD) of 8.4 +/- 4.6 microg/ml. The IC50 of fresh surgical spleen-cell specimens ranged from 0.34 microg/ml to >100 microg/ml in a 48 h incubation, with a mean +/- SD of 66.5 +/- 37.7 microg/ml. When the antitumor activity of MKT-077 was compared between gastric cancer cells and spleen cells obtained from the same patient, the concentration-dependent antitumor activity of this agent was obvious in the cancer cells, while no significant cytotoxicity was observed in the spleen cells. The fresh surgical specimens of gastric cancer showed higher sensitivity to MKT-077 than did spleen cells at a concentration of 30 microg/ml, with a statistically significant difference at P < 0.05. CONCLUSIONS: The selective antitumor activity of MKT-077 was confirmed using fresh surgical specimens and warrants further investigation.

Antineoplastic Agents↗
PubMed1998

Discontinuous total parenteral nutrition prevents postischemic mitochondrial dysfunction in rat liver.

Although discontinuous total parenteral nutrition (d-TPN) has recently been favored for clinical use over continuous total parenteral nutrition (c-TPN) to ameliorate liver dysfunction, mechanisms for the protection against postoperative liver dysfunction remain unknown. This study aimed to examine differences in mitochondrial function in d-TPN- and c-TPN-pretreated livers during ischemia-reperfusion. Rat livers pretreated with d-TPN or c-TPN were perfused with Krebs-Ringer buffer and were exposed to 25% low-flow hypoxia followed by reperfusion. Intrahepatic mitochondrial membrane potential (triangle up) and cell viability were assessed by dual-color digital microfluorography using rhodamine 123 (Rh123) and propidium iodide (PI), respectively. In response to hypoxia, livers pretreated with c-TPN, d-TPN, and an ordinary chow diet exhibited a significant triangle up reduction among the entire lobules. Upon reperfusion, the regional triangle up values further decreased in the c-TPN liver, whereas those in the d-TPN-treated or chow-treated livers displayed a rapid recovery toward the control levels. The severity of cell injury did not differ among the groups, showing that the reperfusion-induced triangle up drop in the c-TPN-pretreated liver is not a consequence of cell injury. Differences in the triangle up drop among the groups appear to occur irrespective of those in the glycogen storage, because the livers undergoing d-TPN display a marked triangle up recovery even when reperfused at the end of a fasted state. These results indicate that c-TPN, but not d-TPN, jeopardizes mitochondrial re-energization and suggest that a circadian pattern of the TPN serves as a potentially beneficial strategy to reduce the risk of postischemic mitochondrial dysfunction in the liver.

Animals↗