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Biomedical subjects

A Kosaka

Publications and source records attributed to A Kosaka.

At least 19 recordsLinked to original sources
PubMed2001

Significance of cadmium concentrations in blood and hair as an indicator of dose 15 years after the reduction of environmental exposure to cadmium.

To evaluate the significance of cadmium (Cd) concentrations in blood (B-Cd) and hair (H-Cd) as an indicator of dose, a cross-sectional study was performed on 40 residents in a Cd-polluted area, Nagasaki Prefecture, Japan, in 1996. In the study area, soil replacement of Cd-polluted rice fields ended in 1981. B-Cd and H-Cd were significantly higher in the study population than in the control subjects. B-Cd was positively correlated with urinary Cd (U-Cd) (Spearman r=0.50, P=0.06 for males and r=0.72, P=0.0001 for females), while H-Cd was weakly or moderately correlated with U-Cd. After adjustment for gender using logistic regression analysis, log(B-Cd) and log(U-Cd), but not log(H-Cd), were significantly associated with the prevalence of increased urinary beta2-microglobulin (P for trend <0.05). These findings suggest that B-Cd is a good indicator of cumulative dose many years after the reduction of environmental exposure to Cd. H-Cd may be weakly or moderately correlated with body burden.

Adult↗
PubMed2001

Mechanism of pH-dependent photolysis of aliphatic amino acids and enantiomeric enrichment of racemic leucine by circularly polarized light.

It has been proposed that the origin of biological homochirality may be the result of irradiation of a racemic sample of amino acids by circularly polarized light (CPL). To determine the mechanism of enantiomeric enrichment, the irradiation of aliphatic amino acids by CPL was undertaken. An enantiomerically enriched sample (e.g., L isomer enrichment from r-CPL) was found to result from the preferential excitation/decomposition of one enantiomer over another via a Norrish Type II mechanism (leucine, valine, and isoleucine), with the enantiomeric excess dependent on the degree of protonation of the amino/carboxylic acid moiety.

Amino Acids↗
PubMed2000

Minimally invasive lung and pleural biopsies using 2-mm and standard thoracoscopic equipment.

Videoendoscopic surgery is commonly used to obtain a definitive diagnosis in a patient with pleural lesions or pulmonary infiltration of unknown etiology. We have performed minimally invasive pleural and lung biopsies, using 2-mm mini-videoscopic instruments supported by standard thoracoscopy via one 11.5-mm port, in 10 patients. These involved 8 patients with diffuse pulmonary infiltration, and two with diffuse pleural thickening. They underwent thoracoscopic pulmonary wedge resection and pleural biopsy using one 11.5-mm port and two or three 2-mm mini-ports. The mean operating time was 37 minutes. This procedure was successful in establishing a definitive diagnosis in each patient. Complications included subacute acceleration in pulmonary infiltration in one patient. No patient complained of pain or discomfort at the 2 mm-thoraco port sites. Healing of this port site resulted in excellent cosmesis. Mini-videoscopic surgery supported by standard thoracoscopic equipment can be used to perform lung or pleural biopsy less invasively than standard thoracoscopic approach.

Aged↗
PubMed2000

Triple carcinomas of the biliary tract associated with congenital choledochal dilatation and pancreaticobiliary maljunction.

We report a rare case of triple carcinomas of the biliary tract associated with congenital choledochal dilatation (CCD) and pancreaticobiliary maljunction (PBM). The patient was a 58-year-old Japanese man who complained of epigastralgia. Ultrasonography and computed tomography revealed an elevated lesion inside the markedly dilated extrahepatic bile duct, thickening of the gallbladder wall, and small polypoid lesions in the gallbladder. Magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography showed CCD and PBM. With a diagnosis of carcinoma of the bile duct and cholesterol polyps in the gallbladder, pylorus-preserving pancreaticoduodenectomy was performed. The resected specimen showed two elevated lesions in the dilated bile duct, cholesterol polyps, and an area of irregular mucosa in the gallbladder. Histopathological examination showed two carcinomas in the bile duct, an adenosquamous cell carcinoma, and a moderately differentiated tubular adenocarcinoma, and a well differentiated tubular adenocarcinoma of the gallbladder. Two years and 6 months after the operation, a solitary metastatic liver tumor was detected. Left hepatic lobectomy was performed. At present, 7 months after the second operation, the patient is doing well with no signs of recurrence. Multiple carcinomas in the biliary tract associated with CCD and PBM, including the details in the present patient, were reviewed.

Bile Duct Neoplasms↗
PubMed2000

Navigation system for neurosurgery with PC platform.

This paper presents a navigation system for a surgical microscope and an endoscope which can be used for neurosurgery. In this system, a wireframe model of a target tumor and other significant anatomical landmarks are superimposed in real-time onto live video images taken from the microscope and the endoscope. The wireframe model is generated from a CT/MRI slice images. Overlaid images are simultaneously displayed in the same monitor using the picture-in-picture function so that the surgeon can concentrate on the single monitor during the surgery. The system measures the position and orientation of the patient using specially designed non-contact sensing devices mounted on the microscope and the endoscope. Based on this real-time measurement, the system displays other useful information about the navigation as well as the rendered wireframe. The accuracy of registration between the wireframe model and the actual live view is less than 2 mm. We tested this system in actual surgery several times, and verified its performance and effectiveness.

Equipment Design↗
PubMed2000

[Arterial infusion chemotherapy for liver metastases from colorectal cancer--therapeutic effects of different protocols].

The therapeutic effects of different protocols for arterial infusion chemotherapy were compared in patients with multiple liver metastases from colorectal cancer. A total of 49 patients with colorectal multiple liver metastases treated in our hospital since 1988 were the subjects. In order to compare the therapeutic effects on the regression of cancer and the survival rate, the subjects were assigned into Groups A-D, which were treated using different protocols. Group A received ADR, EPI, CDDP or 5-FU alone at first. If this drug was not effective, it was replaced with another of those mentioned here, and so on. Group B received CDDP 50 mg on day 1, 5-FU 500 mg/day from day 2 to day 7 and 5-FU 500 mg/day for 2 weeks thereafter (FP treatment). Group C received CDDP 50 mg at the time of reservoir insertion and 5-FU 1,000 mg for 5 hours thereafter (WHF treatment). Group D received 5-FU 1,000 mg for 24 hours on day 1, day 3, and day 5 of every week with combination of CDDP 5-10 mg/day from day 1 to day 5 and none on day 6 and day 7 (intermittent F + low-dose P treatment) for 3 weeks. The response rate was 33% for Group A (n = 18), 46% for Group B (n = 13), 25% for Group C (n = 8) and 80% for Group D (n = 10), showing significant differences between Group D and other groups. The 1-year survival rate was 50% for Group A, 46% for Group B, 29% for Group C and 89% for Group D. Significant differences in survival rate were found between Group B and D, and Group C and D.

Antineoplastic Agents↗
PubMed1999

Identification of surface residues of the monocyte chemotactic protein 1 that affect signaling through the receptor CCR2.

The CC chemokine, monocyte chemotactic protein, 1 (MCP-1) functions as a major chemoattractant for T-cells and monocytes by interacting with the seven-transmembrane G protein-coupled receptor CCR2. To identify which residues of MCP-1 contribute to signaling though CCR2, we mutated all the surface-exposed residues to alanine and other amino acids and made some selective large changes at the amino terminus. We then characterized the impact of these mutations on three postreceptor pathways involving inhibition of cAMP synthesis, stimulation of cytosolic calcium influx, and chemotaxis. The results highlight several important features of the signaling process and the correlation between binding and signaling: The amino terminus of MCP-1 is essential as truncation of residues 2-8 ([1+9-76]hMCP-1) results in a protein that cannot stimulate chemotaxis. However, the exact peptide sequence may be unimportant as individual alanine mutations or simultaneous replacement of residues 3-6 with alanine had little effect. Y13 is also important and must be a large nonpolar residue for chemotaxis to occur. Interestingly, both Y13 and [1+9-76]hMCP-1 are high-affinity binders and thus affinity of these mutants is not correlated with ability to promote chemotaxis. For the other surface residues there is a strong correlation between binding affinity and agonist potency in all three signaling pathways. Perhaps the most interesting observation is that although Y13A and [1+9-76]hMCP are antagonists of chemotaxis, they are agonists of pathways involving inhibition of cAMP synthesis and, in the case of Y13A, calcium influx. These results demonstrate that these two well-known signaling events are not sufficient to drive chemotaxis. Furthermore, it suggests that specific molecular features of MCP-1 induce different conformations in CCR2 that are coupled to separate postreceptor pathways. Therefore, by judicious design of antagonists, it should be possible to trap CCR2 in conformational states that are unable to stimulate all of the pathways required for chemotaxis.

Amino Acids↗
PubMed1999

Solid cystic tumor of the pancreas in elderly men: report of a case.

Solid cystic tumor of the pancreas is a primary pancreatic neoplasm of unknown etiology that most commonly occurs in young women and ordinarily contains hemorrhagic tissue. We report herein the unusual case of a 75-year-old man found to have a solid cystic tumor in the body and tail of the pancreas, who is the oldest such male patient to be documented in Japan. The results of laboratory data and imaging studies indicated that the patient had a nonfunctioning islet tumor or solid cystic tumor of the pancreas, and distal pancreatectomy with splenectomy was performed. The diagnosis of solid cystic tumor was confirmed based on macroscopic and histological findings of the resected pancreatic tumor. The patient is currently in good health, without any signs of tumor recurrence 1 year and 4 months after his operation. A total of 181 cases of solid cystic tumors of the pancreas reported in the Japanese literature, including our case, were reviewed to evaluate the clinical differences between patients aged 50 years or over and those younger than 50 years.

Aged↗
PubMed1999

Successful surgical treatment for implanted intraperitoneal metastases of ruptured small hepatocellular carcinoma: report of a case.

We report herein the case of a 53-year-old man with disseminated intraperitoneal metastases caused by the rupture of small hepatocellular carcinoma (HCC). He was admitted to our hospital in shock after suffering a trauma injury to the upper abdomen. Ultrasonography revealed a massive hemoperitoneum. At surgery, 4000 ml of blood was drained from the abdominal cavity and a ruptured tumor, 2 cm in diameter, was found in the right lobe of the liver. The tumor was resected with an adequate surgical margin and subsequent microscopic examination confirmed a diagnosis of moderately differentiated HCC without associated liver cirrhosis. The patient was readmitted 14 months later following the development of right lower quadrant pain. Ultrasonography and computed tomography revealed extrahepatic abdominal tumors, and abdominal angiography demonstrated four intraperitoneal tumors. At surgery, four implanted metastases adhered to the greater omentum were found and resected. No other tumors were detected. Microscopically, all four tumors were confirmed as moderately differentiated hepatocellular carcinoma. Ruptured HCC may lead to implanted intraperitoneal metastasis, but rupture of small HCC is very rare. While hepatic resection is the treatment of choice for ruptured HCC, according to our review of the literature, only a few patients have survived long-term after resection of implanted metastasis.

Adult↗
PubMed1999

Surgical management of idiopathic tracheal stenosis.

Most nonmalignant upper tracheal stenoses are caused by prolonged endotracheal intubation or tracheostomy, and idiopathic stenosis is uncommon. A 43-year-old woman complained of increasing shortness of breath during exercise over a year prior to admission. She had no significant past medical history, including endotracheal intubation. Bronchoscopy and tracheal tomography revealed nonmalignant circumferential upper tracheal stenosis 20 mm long. Single-stage surgical resection with cricotracheal anastomosis completely relieved her respiratory symptoms. Idiopathic tracheal stenosis is extremely rare, and the treatment of choice is surgery.

Adult↗
PubMed1999

Opposite regulation of the expression of cyclin-dependent kinase inhibitors during contact inhibition.

Contact inhibition is a well-known phenomenon, but the details of its mechanism are poorly understood. Recently, cyclin-dependent kinase inhibitors have been studied intensively with respect to their regulatory role in the cell cycle, and of them, p27(Kip1) is particularly involved in contact inhibition. p27(Kip1) is believed to be regulated primarily through posttranscriptional mechanisms. We now report that cyclin-dependent kinase inhibitors, including p27, are regulated differently at the mRNA level during contact inhibition in murine BALB/c-3T3 fibroblasts. The mRNA expression of p15, p16, and p27 was up-regulated as the cell density increased, but, on the contrary, the mRNA level of p21(Cip1/WAF1/Sdi1) markedly decreased when the cells became confluent. The protein levels of these genes were regulated in the same way as their mRNA levels, and cyclin-dependent kinase-2 activity was markedly inhibited on density-mediated growth arrest of the cells. These results indicate that the regulation of mRNA expression of cyclin-dependent kinase inhibitors appears to contribute to their protein levels and to the arrest of cell growth through contact inhibition.

3T3 Cells↗
PubMed1999

[Efficacy of intra-arterial chemotherapy on life prolongation in patients with hepatic metastasis from colorectal cancer].

The efficacy of intra-arterial chemotherapy for life prolongation was investigated in patients with hepatic metastasis from colorectal cancer who visited our hospital from Jan. 1989-Mar. 1999, but without any other remote metastasis when the presence of their hepatic metastasis was detected. The subjects were assigned to 4 groups; group A (n = 8) was only treated by hepatectomy, group B (n = 27) by intra-arterial chemotherapy combined with hepatectomy, group C (n = 42) with intra-arterial chemotherapy alone, and group D (n = 23) by systemic chemotherapy through intra-venous or oral administration. The survival rates of these groups were determined, and the recurrence risk after hepatectomy was compared between group A and B. Further, the survival rate of the patients treated by intra-arterial chemotherapy was compared between the cases of PD and not-PD (including CR, PR, and NC). The median survival in cases of H1 and H2 was 405 days for group A, 1,018 days for group B and 245 days for group C, showing that group B had a significantly more favorable prognosis than either group A or group C. There were also significant differences in the median survival of H3 cases between group C (422 days) and group D (113 days). One-year cumulative recurrence risks in the residual livers of group A and group B were 79% and 28%, respectively. Thus, significant differences in the recurrence risk were found in the two groups. Meanwhile, the median survival of PD and non-PD cases was 240 and 588 days, respectively. These results suggested that local control by intra-arterial chemotherapy is useful for life prolongation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

[Effect of combination chemotherapy with mitomycin C and cisplatin on advanced gastric carcinoma].

A 71-year-old male with advanced gastric carcinoma with paraaortic lymph node metastases underwent distal gastrectomy. Cisplatin (CDDP) 50 mg/body was administered intravenously (i.v.) on day 1 followed by the administration of 5-fluorouracil 500 mg/body/day i.v. on day 2 through day 7. After two courses of this regimen, further enlargement of paraaortic lymph nodes was revealed by CT scan, and chemotherapy was suspended. Multiple liver and lung metastases were diagnosed 6 months after initial diagnosis, and mitomycin C (MMC) 10 mg/body i.v. was administered on day 1 followed by CDDP 50 mg/body i.v. on day 2. After three courses of this regimen, partial response of the liver metastases and complete response of the lung metastases were observed, and the general condition was markedly improved without any adverse effect except slight nausea. Though the patient died of brain metastases one year after initial diagnosis, the combination chemotherapy with MMC and CDDP was nevertheless thought to improve his quality of life.

Adenocarcinoma, Papillary↗
PubMed1998

Giant leiomyosarcoma of the remnant stomach: report of a case.

We describe herein the case of a 73-year-old woman who developed a giant leiomyosarcoma in the remnant stomach 4 years after undergoing a distal gastrectomy for gastric carcinoma. Abdominal ultrasonography and computed tomography revealed a huge tumor, 22 cm in maximum diameter, in the left hypochondrial region. Selective abdominal angiography showed a hypervascular tumor fed by the branches of the splenic artery and left inferior phrenic artery. The tumor arose from the posterior wall of the remnant stomach, and demonstrated marked extragastric growth and direct invasion of the pancreas, transverse colon, and diaphragm on the left side. Total resection of the remnant stomach with en bloc resection of these adjacent organs was subsequently carried out. We reviewed the Japanese literature on this extremely rare tumor and evaluated its clinical profile. In comparison with leiomyosarcoma of the unresected stomach, that of the remnant stomach more frequently showed endogastric-type growth and was accompanied by ulceration of the gastric mucosa. The prognosis of patients with leiomyosarcoma of the remnant stomach appears to be greatly affected by the presence of liver metastases and the tumor diameter, similar to that of patients with leiomyosarcoma of the unresected stomach.

Aged↗
PubMed1998

Treatment of pancreas head carcinoma in a 91-yr-old man. Report of a case successfully treated with pylorus-preserving pancreatoduodenectomy.

The case of a 91-yr-old man who had a tumor of the pancreas head successfully resected is reported. He was admitted to our hospital because of obstructive jaundice, and then percutaneous transhepatic biliary drainage (PTBD) was performed. Cholangiography via PTBD tube showed marked stenosis of the bile duct in the head of the pancreas. Endoscopic retrograde pancreatography (ERP) showed obstruction of the main pancreatic duct in the head of the pancreas, and carcinoma in the head of the pancreas was diagnosed. Abdominal angiography showed stenosis of the celiac trunk caused by compression from the median arcuate ligament, but no tumor stain or encasement in the pancreas was detected. Because the patient had lived an extremely healthy life and had no serious concurrent disease before admission, laparotomy was performed. The tumor in the head of the pancreas was about 2 cm in diameter and restricted inside the pancreas. Pylorus-preserving pancreatoduodenectomy (PpPD) with regional lymph node dissection was performed. The tumor was 1.5 cm in its maximal diameter, and histopathologically was diagnosed as an invasive ductal carcinoma of the pancreas with moderately differentiated tubular adenocarcinoma. The patient had an uneventful postoperative course and now, 3 yr after surgery, he is doing very well and leading a normal daily life.

Aged↗
PubMed1998

Successful surgical management of penetrating cardiac injury.

A 60-year-old Asian man who suffered penetrating thoracoabdominal injuries was admitted to our hospital in a state of shock. Because the results of a chest computed tomogram (CT) strongly suggested a left ventricular injury, an emergency thoracotomy was performed. A laceration of the left ventricle (3 cm) was sutured and was closed without cardiopulmonary bypass, and coexisting lacerations of the superior mesenteric artery (SMA) and small bowel were surgically repaired. During the procedure, cardiac arrest occurred, but the patient recovered without any apparent neurologic deficit. Postoperative examinations using echocardiogram, CT, and cardiac catheterization revealed a delayed rupture of the left ventricle. On the 28th day after surgery, he was transferred to another hospital for elective cardiac surgery. Primary management of penetrating cardiac injury is discussed in this report.

Abdominal Injuries↗
PubMed1998

Arteriovenous malformation of the rectum: report of a case.

We report herein the case of a 38-year-old man found to have a rectal arteriovenous malformation (AVM). The patient was admitted to our hospital for investigation of fresh anal bleeding and general malaise. Barium-enema examination showed a slightly elevated lesion in the rectum, and a selective superior rectal angiogram subsequently revealed an AVM in the peripheral region of the superior rectal artery, which was presumed to be the cause of the anal bleeding. Colonoscopic examination disclosed a submucosal tumor-like lesion in the left posterior wall of the rectum, 3cm above the anal verge. After marking the boundaries by clipping, transanal resection of the lesion was performed. Histological examination revealed an irregularly expanded arteriovenous aggregation in the submucosal layer. The patient had a favorable postoperative course, and no residual AVM was seen on a postoperative selective inferior mesenteric arteriogram. There have been no signs of recurrence in the 2 years since his operation.

Adult↗