PubMed Health⌕ Search

Biomedical subjects

N Yamaoka

Publications and source records attributed to N Yamaoka.

At least 19 recordsLinked to original sources
PubMed2000

Resistance induction in barley coleoptile cells by intracellular pH decline.

Cytoplasmic acidification in suspension-cultured plant cells has been characterized as a common intracellular response of some kinds of plant cells to elicitors. Expression of various defense genes in these cells has been increased by the cytoplasmic acidification itself without treatment by elicitors. It is not evident, however, whether or not cells with acidified cytoplasm actually exhibit resistance to the pathogen because of the lack of an adequate infection system between cultured plant cells and some pathogens. Using barley coleoptiles rather than suspension-cultured cells, we demonstrated both detection of cellular pH decline and increased resistance to Blumeria graminis. The cytoplasmic pH of barley coleoptile cells floated on 1 mM citrate buffer (CB), pH 4.0, became 0.5 unit lower than that of cells floated on 1 mM CB, pH 8.0, within 30 min after treatment. The penetration efficiency of B. graminis into the coleoptile was decreased in a pH-dependent manner; that is, when the coleoptiles were floated on 1 mM CB, pH 8.0, the penetration efficiency of the fungi was about 80%. In contrast, when the coleoptiles were floated on acidic buffers, the penetration efficiency decreased in parallel the decline of pH and the penetration efficiency reached 0% when coleoptiles were floated on 1 mM CB, pH 4.0. Morphogenesis of appressoria on the coleoptiles floating on CB was not influenced. The lowered penetration efficiency at lower pH was partially cancelled when the barley coleoptiles were irradiated with UV for 5 min prior to B. graminis inoculation. These findings suggest that the decline in cytoplasmic pH in barley coleoptile cells increases resistance to the pathogenic fungus B. graminis.

Cytoplasm↗
PubMed1999

An aberrant left subclavian artery aneurysm with right aortic arch: report of a case.

The case of a 41-year-old man who developed an aneurysm in his aberrant left subclavian artery is described. The patient had a right aortic arch. After a successful aortosubclavian artery bypass, symptoms due to brain ischemia disappeared. This is a very rare disease that is sometimes associated with an aortic anomaly, therefore the optimal therapeutic procedure need to be carefully selected, including the operative indications and approach.

Adult↗
PubMed1999

[Surgical treatment of lung cancer with combined resection of the aorta or superior vena cava].

Until December 1997, 699 cases of lung cancer were resected in our institute. Four cases of invasion into the aorta and seven cases of invasion into the superior vena cava were also operated and each vessels were reconstructed. Two pneumonectomies and nine lobectomies were performed. Four cases of squamous cell carcinoma, three of adenocarcinoma, three of large cell carcinoma and one of adenosquamous carcinoma were found on pathological examination. Four cases of N0, four of N2 and two of N3 were also detected on pathological lymph node evaluation. One case was stage IV with metastasis of ipsilateral axillar lymph nodes and the others were stage IIIB. With respect to pathological curability, absolutely noncurative operation was performed in all cases involving the aorta and absolutely noncurative in four and relatively curative three in cases involving the superior vena cava. During resection and reconstruction of the aorta, three cases received temporary blood supplying bypass and one case was underwent temporary clamping. Two cases developed bilateral lower extremity paralysis. During resection and reconstruction of the superior vena cava, one case underwent intraluminal temporary blood supplying bypass, two received sideclamping and four were reconstructed with double artificial grafts for bilateral innominate veins. Two cases who underwent resection of the aorta died within one year and one is alive after nine months of operation. Five cases who underwent resection of the superior vena cava died due to cancer. One case of N0 and relatively curative is alive in free of recurrence after seven years and six months of operation and another case who had brain metastasis resected is alive after two years and two months of pulmonary operation. Careful selection should be made for resection of the aorta because the prognosis is usually poor. In the resection of the superior vena cava, good prognosis is expected in some cases (N0, relatively curative) and quality of life is expected to improve with the prevention of the superior vena cava syndrome. Aggressive resection should be considered for lung cancer invasion into the superior vena cava.

Adult↗
PubMed1999

[Methicillin-resistant Staphylococcus aureus (MRSA) mediastinitis after cardiovascular operations].

We described three cases of poststernotomy mediastinitis caused by MRSA. The first case 74-year-old woman who had undergone emergent CABG was treated by continuous closed irrigation and consecutive omental transfer. She was suffered from multiple organ failure and died. The other two cases 50-year-old woman and 66-year-old man after double valves replacement and total aortic arch replacement were managed successfully with simultaneous combination of surgical debridement and placement of omental flap. It was seemed that early aggressive surgical procedures before deterioration of general conditions associated with improvement of mortality. Additionally, it was considered that to avoid residual dead space in presternum as well as in mediastinum was essential to decrease the morbidity and hospital stay, especially in case of MRSA infection.

Aged↗
PubMed1998

Changes in expression of the antigen recognized by monoclonal antibody A7 in human pancreatic carcinoma cells following exposure to anticancer agents.

Techniques which can increase the expression level of tumor-associated antigens may improve immunotargeting therapy. We studied the reactivity of MAb A7 toward an antigen expressed on the surface of the human pancreatic cancer cell line HPC-YS after treatment with various antitumoral agents. When we applied 1 microg/ml mitomycin C (MMC) or 0.1 microg/ml neocarzinostatin (NCS) for 1 h, A7 recognizing antigen expression was enhanced until 24 h after the treatments. At a dose that completely suppressed cell growth, increased antigen expression was maintained for 96 h. Therefore, this study suggests that the combined application of an anticancer drug and MAb A7 may be useful for immunotargeting chemotherapy.

Antibiotics, Antineoplastic↗
PubMed1998

Targeted chemotherapy in mice with peritoneally disseminated gastric cancer using monoclonal antibody-drug conjugate.

The murine monoclonal antibody A7 (MAb A7) is reactive against most human gastric cancer cell lines. Using a nude mouse peritoneal dissemination model of human gastric cancer, we investigated targeted chemotherapy using a conjugate of neocarzinostatin (NCS) with MAb A7 (A7-NCS). After demonstrating cytotoxicity of the complex against the human gastric cancer cell line MKN45 in vitro, we intraperitoneally injected A7-NCS, NCS or saline into nude mice bearing peritoneally disseminated human gastric cancer. A7-NCS inhibited peritoneal dissemination significantly more effectively than NCS. MAb A7 may prove to be an effective carrier for antineoplastic drugs in patients with peritoneal dissemination of gastric cancer.

Animals↗
PubMed1998

Partial deficiency of hypoxanthine-guanine phosphoribosyltransferase manifesting as acute renal damage.

A 32-year-old man who had had frequent gouty arthritis over the past 17 years, was admitted for acute renal failure. Acute renal failure was improved rapidly after medication was resumed and the patient was sufficiently hydrated. The hypoxanthine-guanine phosphoribosyltransferase (HPRT) activity in the patient had been reduced to about 30% of the normal control. Therefore we considered that this patient suffered from a partial deficiency of HPRT. A point mutation of HPRT gene 68G (guanine) to T (thymine) was detected. This is a mutation that has not been previously reported. Familial analysis indicated that his mother and sister were heterozygotes.

Acute Kidney Injury↗
PubMed1998

[Surgical results of T3 lung cancer with combined resection].

Forty six patients with T3 lung cancer underwent pulmonary resection in our institutes. The actual survival rate of lung cancer patients with invasion in pericardium at five years is significantly higher than that in parietal pleura and chest wall (63.5% vs 13.2%, 11.1%). The survival rate of patients with large cell lung cancer is significantly lower than that with squamous cell lung cancer and small cell lung cancer (0.0% vs 39.9%, 16.7%). It is suggested that T3 large cell lung cancer patients might be contraindication of pulmonary resection. The five-year survival rate of patients with n0, n1, n2 disease are 35.5%, 66.7%, 6.7% respectively. There are significant differences in survival rate between patients with n0 + n1 and n2 disease.

Adult↗
PubMed1997

The structure and function of a soybean beta-glucan-elicitor-binding protein.

beta-Glucan elicitor (GE), released from the cell wall of the phytopathogenic fungus Phytophthora megasperma by soybean glucanases, causes defense reactions in soybean. A GE-binding protein (GEBP) was purified from the membrane fraction of soybean root cells, and its cDNA was isolated. Expression of the cDNA clone in tobacco suspension cultured cells and in Escherichia coli conferred GE-binding activity to both. An antibody against the recombinant protein was found to inhibit the GE binding with the soybean cotyledon membrane fraction as well as the resulting accumulation of phytoalexin. Immunolocalization assays indicated that the GEBPs are located in the plasma membrane of root cells. These results suggest that the cDNA encodes a GE receptor and may mediate the signaling of the elicitor.

ATP-Binding Cassette Transporters↗
PubMed1997

Salivary drug monitoring of irinotecan and its active metabolite in cancer patients.

To assess the clinical usefulness of salivary monitoring of irinotecan (CPT-11) and its active metabolite (SN-38), we examined the clinical pharmacological profile of both drugs in 9 patients with thoracic malignancies who received 60 mg/m2 CPT-11 (21 courses). Plasma and unstimulated whole saliva were collected over a 24-h period, and concentrations of CPT-11 and SN-38 were measured by high-performance liquid chromatography. Both CPT-11 and SN-38 were detectable in saliva, and the concentration-time curves in plasma and saliva showed a very similar pattern. A good correlation was observed between the saliva concentration (C3) and the plasma concentration (Cp) for both CPT-11 and SN-38 (r = 0.732, P < 0.0001 and r = 0.611, P < 0.0001, respectively). The area under the concentration-time curve calculated for saliva (AUCs) correlated with that generated for plasma (AUCp) for both CPT-11 and SN-38 (r = 0.531, P = 0.012 and r = 0.611, P = 0.0025, respectively). These results suggest that it may be feasible to use saliva instead of plasma for pharmacokinetics/pharmacodynamics studies of CPT-11.

Aged↗
PubMed1997

An asymptomatic germline missense base substitution in the hypoxanthine phosphoribosyltransferase (HPRT) gene that reduces the amount of enzyme in humans.

A 40-year-old normouricemic (5.5 mg/dl) male showed 46% hemolysate and 37% lymphoblast hypoxanthine phosphoribosyltransferase (HPRT) activities but was otherwise completely free of symptoms. His genomic DNA and cDNA had a missense base substitution (CAT-to-CGT in codon 60) leading to the amino-acid substitution His-to-Arg. Western blot analysis revealed that the amount of HPRT protein in lymphoblasts from this individual was 25%-50% of normal cells, suggesting that the decrease in the amount of enzyme protein was responsible for the partial deficiency. This provides the first clear evidence that a genomic missense mutation at the HPRT locus leads to a decrease in the amount of the enzyme protein but that otherwise it has no evident adverse effects in the hemizygote (asymptomatic mutation).

Adult↗
PubMed1997

Enhancement of tumor radio-response by irinotecan in human lung tumor xenografts.

We investigated the ability of 7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxycamptothecin (CPT-11) to increase tumor radio-response in vivo using human lung tumor xenografts. The xenografts were treated with (1) CPT-11 (10 mg/kg) intraperitoneally on days 1, 5 and 9, (2) single dose radiation (10 Gy/leg) on day 1, or (3) a combination regimen of both treatments in which radiation was given 1 h after the first dose of CPT-11. DNA flow cytometry studies were performed to define the cell cycle changes following treatment for 1 to 12 h with 0, 0.5, 2.0 or 8.0 ng/ml SN-38, the major active metabolite of CPT-11. In both small cell lung cancer (MS-1) and small cell/large cell carcinoma (LX-1) xenografts, combination treatment resulted in significant tumor regression compared with the use of CPT-11 (P = 0.0005, 0.0053) or radiation treatment (P = 0.00221, 0.0035) alone. Neither severe body weight loss nor enhanced skin reaction was observed following the combined treatment. In flow cytometry studies, the proportion of cells in G2/M-phase, the most radio-sensitive phase, increased after 1 h exposure to the lowest dose of SN-38 (0.5 ng/ml). These findings suggest that CPT-11 is a potent radiosensitizing agent, and that its activity is related to the cell cycle. This is the first report to indicate that CPT-11 serves as a radiosensitizer in vivo.

Animals↗
PubMed1997

[A resected case of bronchogenic cyst of the left hemidiaphragm with elevated serum CA19-9].

A rare case of bronchogenic cyst of the left hemidiaphragm is reported. A 53-year-old woman referred to our institution for an abnormal shadow on chest roentgenogram. Chest X-ray showed a 6 x 6 cm mass in the left lower lung filed. The margin of the mass was clear and the surface was smooth. The lateral view showed a mass on the diaphragm with the extrapleural sign. Chest CT demonstrated the mass as a multi loculated cyst. Celiac angiography demonstrated the branch of the inferior diaphragmatic artery at the margin of the mass. Her serum CA19-9 level was 470 U/ml. The patient underwent surgical exploration. Operative findings showed the smooth surface mass was on the diaphragm covered with pleura. Resected tumor was large as 7.5 x 6.5 x 4.0 cm. The surface was smooth and white-yellowish, and the cut surface presented a multi loculated cyts. Histopathological examination showed a bronchogenic cyst. CA19-9 in the cyst fluid was elevated as 445,900 U/ml. The serum CA19-9 level returned to normal after the operation.

Bronchogenic Cyst↗
PubMed1996

Successful application of an omental pedicle flap in delayed repair of a perforated esophageal diverticulum: report of a case.

Mediastinitis resulting from a perforated esophageal diverticulum is a potentially fatal complication and the surgical treatment of persistent esophagomediastinal fistula may be difficult. In this report, we describe the successful application of an omental pedicle flap in the delayed repair of a perforated esophageal diverticulum. A 53-year-old man presented with chest and back pain and a diagnosis of perforated esophageal diverticulum was subsequently confirmed. After receiving conservative treatment, he was referred to our department and underwent surgical repair 6 months following the onset of the perforation. Through a right thoracotomy, the mucosal layer of the esophagus around the diverticulum was sutured, and an omental pedicle flap was used to cover the suture line and obliterate the fistulous tract. His postoperative course was uneventful and the suture line healed well. The successful treatment of this patient reinforces our belief that wider application of the omental pedicle flap can be expected in the field of thoracic surgery.

Diverticulum, Esophageal↗
PubMed1996

Bioavailability of 50- and 75-mg oral etoposide in lung cancer patients.

This study was designed to determine the bioavailability of etoposide capsules administered orally at doses of 50 and 75 mg. Patients with inoperable or relapsed lung cancer, who had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 and adequate organ function, were eligible. A group of 17 patients were evaluable, all of whom were 75 years old or less, with an ECOG performance status of 0 or 1. The bioavailability of oral etoposide was determined by measuring the area under the etoposide plasma concentration versus time curve (AUC) on days 1, 10 and 21 during a once-daily regimen of oral administration for 21 consecutive days and comparing the value with the AUC achieved following intravenous administration 1 or 2 weeks after the last oral dose. The bioavailability of 50, 75 and 100 mg oral etoposide was determined in six, nine and two patients, respectively. The mean etoposide bioavailabilities (+/- SD) of the 50-mg and 75-mg doses were 47 +/- 11% and 59 +/- 18%, respectively, and of the 100-mg dose in two patients were 51% and 33%, respectively. There was no statistically significant difference in bioavailability between the 50-mg and 75-mg doses. The bioavailability of low-dose oral etoposide was the same as that reported in previous higher dose oral etoposide bioavailability studies and that shown on the package insert supplied by the manufacturer. Improved bioavailability of low-dose oral etoposide was therefore not observed in a population of Japanese patients.

Administration, Oral↗
PubMed1996

No alteration in DNA topoisomerase I gene related to CPT-11 resistance in human lung cancer.

Mutations and reduced expression of DNA topoisomerase I (topo I) gene have been shown to be important in the acquisition of resistance to camptothecin and its analogues in vitro, but their significance has not been verified in vivo. We investigated possible topo I gene mutations and topo I mRNA expression levels in 127 samples obtained from 56 patients with lung tumors, including patients who had developed clinical resistance to topo I inhibitors. No mutations were detected in any of the samples examined and expression levels did not differ significantly between clinically resistant cases and others. However, the topo I mRNA expression level was significantly higher in small cell lung carcinomas than in non-small cell lung carcinomas (P < 0.05). These results suggest that topo I mRNA levels may affect CPT-11 sensitivity in human lung cancer. However, topo I gene mutations and reduced topo I mRNA expression may not be the main mechanism of clinically acquired resistance to camptothecin analogues in vivo.

Adult↗