Biomedical subjects

Toru Koyama

Publications and source records attributed to Toru Koyama.

12 recordsLinked to original sources

PubMed2006

Subtle computed tomography abnormalities in cerebral deep sinus thrombosis.

A patient with cerebral deep sinus thrombosis, which was not diagnosed on the first examination, is reported. A 46-year-old woman presented with headache and vomiting. Neurological examination and a brain computed tomography (CT) scan showed no obvious abnormal findings. The patient suffered disturbed consciousness on the day after the examination, and was admitted to our emergency centre. A CT scan and magnetic resonance imaging revealed an ischaemic lesion in the left basal ganglia, suggesting deep sinus occlusion. Anticoagulant therapy was administered. One day after admission, a CT scan showed a haematoma and severe brain swelling in the same region. Cerebral angiography demonstrated a straight sinus occlusion. Intracranial pressure was not controlled with hypothermia, and the patient died 25 days after admission. Review of the initial CT scan revealed subtle, early findings of deep venous thrombosis that were missed on first examination.

Anticoagulants↗

PubMed2006

Middle cerebral artery occlusion associated with acute myocardial infarction in the perioperative period--case report.

A 68-year-old woman with no history of cardiac events suffered acute myocardial infarction after surgery for middle cerebral artery (MCA) occlusion manifesting as transient left motor weakness. Diffusion-weighted magnetic resonance imaging revealed multiple infarctions in the right cerebral hemisphere. Magnetic resonance angiography and cerebral angiography demonstrated an occlusion at the horizontal segment of the right MCA and no collateral circulation. Cerebral blood flow study 6 weeks after the initial presentation indicated decreased blood flow in the right cerebral hemisphere. Superficial temporal artery-MCA anastomosis was conducted to prevent recurrent cerebral infarction. Two hours after surgery, her systolic blood pressure fell to 60 mmHg and her consciousness worsened. Emergency coronary angiography indicated occlusion of the right coronary artery. Percutaneous coronary intervention was successfully performed and the subsequent course was uneventful. Preoperative evaluation of the coronary artery may be necessary before surgery for cerebral ischemic disease in both the intracranial and extracranial arteries.

Aged↗

PubMed2006

Beneficial effects of protein-bound polysaccharide K plus tegafur/uracil in patients with stage II or III colorectal cancer: analysis of immunological parameters.

Protein-bound polysaccharide K (PSK) increased the 5-year disease-free survival rate and reduced the risk of recurrence in a randomised, controlled study for stage II and III colorectal cancer. In order to elucidate the disease-free survival benefits with PSK and what immunological markers could indicate a PSK responder, serial changes in immunological parameters were monitored in the study. PSK decreased the mean serum immunosuppressive acidic protein (IAP) level, and increased the mean population of natural killer (NK) cells compared with the controls. The 5-year disease-free and overall survival rate for patients with serum IAP values or=8% at 3 months after surgery, PSK conferred a significantly better (p=0.038) 5-year disease-free survival (86.7%; 95% CI: 74.5-98.8%) compared to the control group (60.0%; 95% CI: 29.6-90.4%). In the proportional hazards model, the presence of regional metastases (relative risk, 3.595; 95% CI: 1.518 to 8.518; p=0.004) and omission of PSK treatment (relative risk, 3.099; 95% CI: 1.202 to 7.990; p=0.019) were significant indicators of recurrence. PSK acts as an immunomodulatory activity and biochemical modulator in stage II or III colorectal cancer. Pre-operative serum IAP values or=8% at 3 months after surgery are possible PSK response predictors.

Adult↗

PubMed2005

A saccular-like dissecting aneurysm of the anterior cerebral artery that developed 2 years after an ischemic event.

BACKGROUND: A rare case of a growing dissecting aneurysm, which was located at the horizontal (A1) segment of the anterior cerebral artery (ACA), is reported. CASE DESCRIPTION: A 53-year-old woman experienced left hemiparesis and alien hand syndrome. A computerized tomography scan showed an infarction in the right frontal lobe, and cerebral angiography revealed a false lumen and intimal flap at the A1 segment of the ACA. Magnetic resonance angiography demonstrated that the stenosis progressed 6 months later and improved 1 year later. Cerebral angiography showed a saccular-like aneurysm 2 years later. The surgery was planned for prevention of aneurysmal rupture. The aneurysm, which was cocoon shaped, was exposed surgically and was resected. Histological examination of the aneurysm showed arterial dissection. The postoperative course was uneventful without additional neurological deficits. CONCLUSION: This is the first case report of A1 dissecting aneurysm presenting with an ischemic event in the literature. The sequential change of the configuration was curious to develop aneurysmal dilatation in 2 years. Long-term follow-up is necessary even after disappearance of the arterial dissection.

Aortic Dissection↗

PubMed2004

Re-occlusion of the superior sagittal sinus after surgical recanalisation.

A 24-year-old woman was struck on the head by a hammer. Because of early signs and symptoms of intercranial hypertension, she underwent surgery for elevation of the depressed fragments which was compressing the superior sagittal sinus (SSS). After operation, the intracranial pressure (ICP) once decreased, but it gradually increased again. After hypothermia and barbiturate therapy, she recovered fully except for partial visual field defect due to brain contusion. A carotid angiogram 28 days after injury revealed complete occlusion of the whole SSS with good collateral circulation. After brain edema had subsided, a follow-up angiogram revealed normal blood flow through the SSS. Elevation of depressed bony fragments is required for a case presenting with early signs and symptoms of intracranial hypertension due to sinus compression. In a case with severe destruction of the SSS, one needs to know that re-occlusion of the dural sinus may occur after surgical recanalisation.

Adult↗

PubMed2004

Mutational analysis of the BAK gene in 192 advanced gastric and colorectal cancers.

The evasion of apoptosis has been linked to the development of cancer. A recent study of a small number of gastric and colorectal cancers found that the BAK gene, which encodes a pro-apoptotic protein, contained somatic mutations in approximately 17% of the samples analyzed. To investigate the precise frequency of BAK mutations, we examined the entire coding sequence of the BAK gene in gastric and colorectal cancers, using polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) analysis and direct sequencing. We could not detect any somatic mutations of the BAK gene in 192 colorectal and gastric cancers. We found only four single-nucleotide substitutions in the coding sequences, which were also found in corresponding normal samples. We conclude that somatic alterations of the BAK gene are rare in colorectal and gastric cancers.

Apoptosis↗

PubMed2002

Frameshift mutations in the MBD4/MED1 gene in primary gastric cancer with high-frequency microsatellite instability.

MBD4/MED1 is a newly identified mismatch repair gene, which is mutated in colon, endometrial, and pancreatic high-frequency microsatellite instability (MSI-H) tumors. To assess its role in gastric cancers, we investigated MBD4/MED1 mutations in sporadic gastric cancers, compared with colon cancers. Frameshift mutations were found in 29% of gastric and 20% of colon MSI-H cancers, but not in any low-frequency microsatellite instability/microsatellite stable cancers. MBD4/MED1 is mutated in gastric cancers as frequently as in colon cancers; these mutations reduce the accuracy of DNA repair, and may lead to cancer progression.

Aged↗

PubMed2002

A hemophagocytic syndrome-like condition after emergency colectomy for perforated colon cancer: report of a case.

Hemophagocytic syndrome is a rare but often fatal condition, and little is known about why this disorder can occur following surgery. We report herein the case of a patient successfully treated for a hemophagocytic syndrome-like condition that developed after emergency right hemicolectomy for a retroperitoneal abscess secondary to perforated colon cancer. The 62-year-old man initially presented after the sudden development of severe right back pain, and computerized tomography scans revealed a retroperitoneal abscess continuous with a tumor in the ascending colon. An emergency right hemicolectomy was subsequently performed. On postoperative day (POD) 2, his blood platelet count suddenly dropped to 1 x 10(4)/microl and histological examination of a bone marrow specimen taken on POD 5 showed abnormal histiocytes that had phagocytosed not only megakaryocytes, but also erythrocytes and leukocytes, and a normocellular marrow with a normal number of megakaryocytes. Hemophagocytic syndrome was suspected, and predonine was administered. The patient's condition improved remarkably and he was discharged on POD 51.

Abscess↗

PubMed2002

Mutation and expression of the beta-catenin-interacting protein ICAT in human colorectal tumors.

BACKGROUND: Aberrant activation of Wnt signaling caused by mutations in the tumor suppressor adenomatous polyposis coli or beta-catenin is a critical event in the development of human colorectal tumors. We have recently identified the ICAT gene, which encodes a small protein that interacts with beta-catenin and represses Wnt signaling. METHODS: We examined the prevalence of mutations in the entire ICAT coding sequence and intronic splice donor and acceptor regions of ICAT by PCR-SSCP and also the expression of the ICAT gene by RT-PCR. RESULTS: The ICAT gene was mapped to chromosome 1p36.1-p36.2, which is implicated in the pathogenesis of various types of cancers. However, no mutations in ICAT were detected among 128 colorectal tumors. Instead, ICAT was found to be overexpressed in almost half of colorectal carcinomas. Cases exhibiting ICAT overexpression showed a significantly higher incidence of well-differentiated adenocarcinoma and positive lymphatic permeation. CONCLUSION: Our results suggest that ICAT is not the putative tumor suppressor on 1p36.1-p36.2, although aberrant overexpression of ICAT may play a role in the pathogenesis of colorectal carcinomas.

Adaptor Proteins, Signal Transducing↗

PubMed2002

Aneurysm originating from the fenestration of the posterior cerebral artery: case report.

OBJECTIVE AND IMPORTANCE: A rare case of an aneurysm arising at the fenestration of the P2 segment of the posterior cerebral artery is reported. CLINICAL PRESENTATION: A 37-year-old man presented with severe headache and disturbance of consciousness. Computed tomographic scanning showed diffuse subarachnoid hemorrhage. Cerebral angiography revealed an aneurysm at the fenestration of the P2 segment of the right posterior cerebral artery. The aneurysm was located at the middle portion of the lower trunk of the fenestration. An unruptured arteriovenous malformation was incidentally found in the right thalamus. INTERVENTION: A right frontotemporal craniotomy with orbitozygomatic osteotomy was made, and the aneurysm was successfully clipped. One year after the operation, gamma knife surgery was performed for the right thalamic arteriovenous malformation. CONCLUSION: This is the first reported case of an aneurysm originating from the middle portion of a fenestrated posterior cerebral artery.

Adult↗

PubMedDate not supplied

Omentoplasty versus no omentoplasty for cervical esophagogastrostomy following radical esophagectomy.

BACKGROUND/AIMS: Omentoplasty--wrapping the omentum around the alimentary tract anastomosis is thought to lower the rate of anastomotic leakage. We evaluated the role of omentoplasty to reinforce cervical esophagogastrostomy after radical esophagectomy. METHODOLOGY: We compared anastomotic leakage, stricture formation, and related deaths in 63 patients who underwent radical esophagectomy and cervical esophagogastrostomy, with (n = 48) or without (n = 15) omentoplasty, between 1995 and 1999. RESULTS: An esophageal anastomotic leakage was diagnosed in 1 of the 48 patients (2.1%) with omentoplasty versus 3 of the 15 patients (20.0%) without omentoplasty (P < 0.01). Anastomotic stricture occurred in 2 (4.2%) of the omentoplasty group and 1 (6.7%) of the no omentoplasty group (P < 0.01). Death within 1 month was zero in the omentoplasty group and one (6.7%) in the no-omentoplasty group, despite no differences in lethal anastomotic leakage. CONCLUSIONS: Omentoplasty of cervical esophagogastrostomy reduced anastomotic leakage. Although promising, these observations require confirmation with a randomized prospective study.

Aged↗

PubMedDate not supplied

Factors affecting the prognosis of anatomical liver resection for liver metastases from colorectal cancer.

BACKGROUND/AIMS: Liver resection has improved the survival of colorectal cancer patients with metastases. However, there are groups at high risk of recurrence after liver resection. This report reviews our results using anatomical liver resection and analyzes the prognostic factors. METHODOLOGY: We analyzed 78 patients who underwent anatomical liver resection of liver metastases from colorectal cancer between June 1988 and March 2002. RESULTS: Twenty-nine patients had synchronous metastases, and 49 had metachronous. The 5-year overall survival rate was 43%. Patients with more than three metastatic tumors had a significantly poorer 5-year recurrence-free survival rate. There was no statistical difference in the 5-year overall survival rate between patients with metachronous metastases (41%) and those with synchronous (44%) metastases. The 5-year overall survival rate was significantly poorer for patients with an interval of 1 year or less between colorectal and liver resections than for patients with a longer interval. Recurrence after liver resection occurred in 38 patients (49%). The recurrences occurred in the lung in 18 patients, in remnant liver in 15 patients, in lymph nodes in 7 patients, and in other organs in 6 patients. CONCLUSIONS: We conclude that anatomical liver resection of liver metastases from colorectal cancer improves survival. Liver metastases that occur within 1 year of colorectal resection may need an interval of observation before liver resection.

Adult↗