Biomedical subjects

M Seki

Publications and source records attributed to M Seki.

At least 109 records · Page 6Linked to original sources

PubMed2000

Differential behavior of VEGF receptor expression and response to TNP-470 in two immortalized human endothelial cell lines.

Angiogenesis consists of endothelial cell proliferation, migration and tube formation. It is useful to investigate endothelial cell behavior using immortalized endothelial cell lines. We characterized cell growth property, growth factor dependency and response to angioinhibitory drugs; TNP-470, staurosporine, radicicol and genistein, using human umbilical vein endothelial cells (HUVECs) immortalized by human papilloma virus (HPV)-16 E6-E7, named HUVECs/E6-E7, and HUVECs/E6-E7 transformed by v-Ki-ras gene, named HUVECs/E6-E7/ras. The dependency to vascular endothelial cell growth factor (VEGF) and basic fibroblast growth factor (bFGF) for cell proliferation decreased in HUVECs/E6-E7, but were restored in HUVECs/E6-E7/ras. Flow cytometric analysis demonstrated that a VEGF receptor KDR/flk-1 was down-regulated in HUVECs/E6-E7 but not in HUVECs/E6-E7/ras. Expression of another VEGF receptor flt-1 was consistent in all cells including HUVECs, HUVECs/E6-E7 and HUVECs/E6-E7/ras. According to the analysis of the angioinhibitory drugs, HUVECs/E6-E7 was obviously resistant to TNP-470, but HUVECs/E6-E7/ras showed similar response compared to HUVECs which suggests that v-Ki-ras signaling pathway is associated with VEGF receptor expression and make HUVECs/E6-E7 sensitive to TNP-470 by modulating the signal transduction cascade. In conclusion, HPV-16 E6-E7 and v-Ki-ras genes have unique growth properties and these immortalized cells are useful for investigating signal transduction pathways of endothelial cells, and for screening of angioinhibitory drugs.

Angiogenesis Inhibitors↗

PubMed2000

Synovial adhesions are more important than pannus proliferation in the pathogenesis of knee joint contracture after immobilization: an experimental investigation in the rat.

OBJECTIVE: To measure intraarticular pannus proliferation after early and prolonged joint immobility using an animal model. METHODS: Forty rats underwent unilateral immobilization of a knee joint with an internal fixator for periods of 2, 4, 8, 16, and 32 weeks. Twenty rats received sham surgery. The knee joints were harvested and processed for histological examination. The synovial intima length and the subintimal area were measured on standardized sagittal sections with image analysis software. The measurements were recorded with regard to their location (anterior or posterior; superior or inferior). RESULTS: Intra and interrater reliabilities for all measurements were > 87.9%. The synovial intima length was smaller in immobilized knees than in controls at all time points. At 4 and 32 weeks, the difference was statistically significant (p < 0.05). The differences were marked in the posterior synovium, where the intima length of immobilized knees was significantly smaller than in controls after 4, 8, 16, and 32 weeks of immobilization (p < 0.05). The subintimal area was comparable in immobilized and control knees at all time points. CONCLUSION: We standardized the quantification of intraarticular pannus in a joint contracture model after immobility of up to 32 weeks' duration. This study revealed a significant decrease in synovial intima length but no change in the subintimal area of immobilized knees compared with controls. The decrease in synovial intima length with immobility suggests that adhesions of synovium villi rather than pannus proliferation are the major pathophysiological changes leading to contracture after immobility.

Animals↗

PubMed2000

[Malignant cardiac lymphoma].

A 65-year-old male was admitted to the hospital in shock. The transesophageal echocardiography showed cardiac tumor in the right atrium. The tumor was resected under cardiopulmonary bypass. It was diagnosed as malignant lymphoma of B-cell type by histological examination. After operation, his general condition became satisfactory. Then he received chemotherapy. Twenty days after operation, however, a mass appeared in the right side of chin. It was diagnosed as malignant lymphoma of the same cell type as in the heart. We searched his body with CT and Ga-scanning. No other lesions were found. After the chemotherapy (CHOP, 6 cycles), the mass disappeared. No recurrence was been observed for six months.

Aged↗

PubMed2000

[Multicenter study of cardiac events and anesthetic management of patients with ischemic heart diseases undergoing noncardiac surgery].

We designed a joint research project to investigate the incidence of ischemic heart diseases in patients undergoing noncardiac surgery and to define the risk of perioperative cardiac complications in these patients. Of the 8358 surgical patients in the 8 departments of anesthesiology between March 1997 and June 1997, 328 (3.9%) had ischemic heart diseases. Among the 328 patients, 54 (16.4%) developed perioperative cardiac events, including myocardial infarction (3 patients) and either lethal or potentially dangerous dysrhythmias (51 patients). Preoperative cardiac assessments were performed while the anesthetic techniques including intensive monitoring and perioperative prophylactic therapy were also employed. Patients with ischemic heart diseases received various types of preoperative evaluation to identify the degree of coronary artery disease and to assess the overall cardiac function. The patients were monitored using a multilead electrocardiogram, an arterial line, a central venous catheter, a pulmonary artery catheter, and by transesophageal echocardiography intraoperatively. Therapeutically, isosorbide, nitroglycerin, beta-blockers, calcium channel blockers, and/or nicorandil were administered to prevent perioperative ischemia. So far, no generally accepted management strategies have been established in patients with cardiovascular disorders based on large-scale outcome trials in Japan. Therefore, nationwide large multicenter trials are awaited with interest in order to establish helpful guidelines to improve the perioperative management and to reduce ischemia in cardiac patients undergoing noncardiac surgery.

Anesthesia↗

PubMed2000

[A multicenter study of cardiac events and anesthetic management of patients with ischemic heart diseases for noncardiac surgery--a follow-up report].

We have conducted a joint research project to investigate the incidence of ischemic heart disease in patients for noncardiac surgery and to define the risk of perioperative cardiac complications in these patients. From September to November 1997 we had 7288 patients scheduled to undergo noncardiac surgery in the 8 departments of anesthesiology. Of these patients, 228 (3.1%) patients had ischemic heart disease, and 30 of them (13.2%) developed perioperative cardiac events. Critical cardiac events, including perioperative myocardial ischemia and lethal arrhythmia, occurred in 7 of these patients. In our region of Japan, 3-4% of surgical patients tend to develop ischemic heart disease and 3.1% of them demonstrated severe cardiac complications perioperatively. Compared with United States we encounter fewer surgical patients with ischemic heart disease, but the risk of developing perioperative cardiac complications in such patients is almost the same for both countries.

Aged↗

PubMed2000

[Labial adhesion in a reproductive woman with difficulties of sexual intercourse and urination: a case report].

A 27-year-old female patient consulted us with chief complaints of difficulties of sexual intercourse and urination. On examination, the labia was found to be extensively fused at the midline, with a pinhole opening. We diagnosed it as labial adhesion. We operated on it under lumbar anesthesia. Four months after the operation, there were no symptoms of recurrence. Labial adhesion is thought to be caused by inflammation, lack of sexual activity and estrogen deficiency. It is not uncommon in children and post-menopausal women, but is extremely rare in reproductive women.

Adult↗

PubMed2000

[Treatment of pressure sores accompanied by infection in outpatients with spinal cord injury].

The occurrence of infection at pressure sore sites due to multiple drug resistant microbes not only delays healing at the time of infection, but it can become a major factor preventing an acceptable level of ADL (activities of daily living) in the home. We studied a method for treating infection in pressure sores in spinal cord injury patients living at home who were commuting to our hospital for treatment. After establishing drug sensitivity in all patients, we instructed patients and their families how to apply dressings using 2% chloramphenicol (CP) ointment, and then studied the status regarding infection and the course of the pressure sores. Considerable Proteus vulgaris, E. faecalis, P. aeruginosa, and methicillia resistant staphylococcus aureus (MRSA) were detected in cultures from all patients. After the start of treatment at home, the casual microbes disappeared over time, and improvement was seen, including according to the Shea classification, with time from the infection. This was thought to be due to a decrease in the frequency of use of CP at the clinic and a subsequent increase in sensitivity. It was inferred from these results that the local administration of antibacterial CP ointment in the home at the time of infection is effective against pressure sores.

Adult↗

PubMed1999

Strand asymmetry of +1 frameshift mutagenesis at a homopolymeric run by DNA polymerase III holoenzyme of Escherichia coli.

We have recently shown that single-base frameshifts were predominant among mutations induced within the rpsL target sequence upon oriC plasmid DNA replication in vitro. We found that the occurrence of +1 frameshifts at a run of 6 residues of dA/dT could be increased proportionally by increasing the concentration of dATP present in the in vitro replication. Using single-stranded circular DNA containing either the coding sequence of the rpsL gene or its complementary sequence, the +1 frameshift mutagenesis by DNA polymerase III holoenzyme of Escherichia coli was extensively examined. A(6) --> A(7) frameshifts occurred 30 to 90 times more frequently during DNA synthesis with the noncoding sequence (dT tract) template than with the coding sequence (dA tract). Excess dATP enhanced the occurrence of +1 frameshifts during DNA synthesis with the dT tract template, but no other dNTPs showed such an effect. In the presence of 0.1 mM dATP, the A(6) --> A(7) mutagenesis with the dT tract template was not inhibited by 1.5 mM dCTP, which is complementary to the residue immediately upstream of the dT tract. These results strongly suggested that the A(6) --> A(7) frameshift mutagenesis possesses an asymmetric strand nature and that slippage errors leading to the +1 frameshift are made during chain elongation within the tract rather than by misincorporation of nucleotides opposite residues next to the tract.

Base Sequence↗

PubMed1999

Selective diapedesis of Th1 cells induced by endothelial cell RANTES.

Differentiated CD4 T cells can be divided into Th1 and Th2 types based on the cytokines they produce. Differential expression of chemokine receptors on either the Th1-type or the Th2-type cell suggests that Th1-type and Th2-type cells differ not only in cytokine production but also in their migratory capacity. Stimulation of endothelial cells with IFN-gamma selectively enhanced transmigration of Th1-type cells, but not Th2-type cells, in a transendothelial migration assay. Enhanced transmigration of Th1-type cells was dependent on the chemokine RANTES produced by endothelial cells, as indicated by the findings that Ab neutralizing RANTES, or Ab to its receptor CCR5, inhibited transmigration. Neutralizing Ab to chemokines macrophage-inflammatory protein-1alpha or monocyte chemotactic protein-1 did not inhibit Th1 selective migration. Whereas anti-CD18 and anti-CD54 blocked basal levels of Th1-type cell adherence to endothelial cells and also inhibited transmigration, anti-RANTES blocked only transmigration, indicating that RANTES appeared to induce transmigration of adherent T cells. RANTES seemed to promote diapedesis of adherent Th1-type cells by augmenting pseudopod formation in conjunction with actin rearrangement by a pathway that was sensitive to the phosphoinositol 3-kinase inhibitor wortmannin and to the Rho GTP-binding protein inhibitor, epidermal cell differentiation inhibitor. Thus, enhancement of Th1-type selective migration appeared to be responsible for the diapedesis induced by interaction between CCR5 on Th1-type cells and RANTES produced by endothelial cells. Further evidence that CCR5 and RANTES play a modulatory role in Th1-type selective migration derives from the abrogation of this migration by anti-RANTES and anti-CCR5 Abs.

Actins↗

PubMed1999

Apoptosis-promoting gene (bax) transfer potentiates sensitivity of squamous cell carcinoma to cisplatin in vitro and in vivo.

Modulation of apoptosis may potentiate the sensitivity of tumor cells to chemotherapeutic agents, thus improving the clinical outcome of cancer treatment. Bax, an apoptosis-promoting member of the bcl-2 family, may be a key factor influencing the chemosensitivity of tumor cells, however, its involvement in cellular sensitivity to anti-cancer drugs remains uncertain in squamous cell carcinoma (SCC). To investigate the role of bax gene expression in modulating cisplatin (CDDP)-induced apoptosis in vitro, an established CDDP-resistant human head and neck SCC (IMC-3 cell line) was transfected with bax gene-bearing mammalian expression vector. Overexpression of the bax gene in CDDP-resistant IMC-3 cells elevated the CDDP susceptibility of tumor cells to a level similar to that of the parental IMC-3 cells. In an in vivo study, percutaneous transfer of apoptosis-promoting bax gene by particle-mediated (gene gun) delivery caused overexpression of Bax in SCC, which was confirmed by immunohistochemical staining, and inhibited the growth of mouse CDDP-resistant SCC. Furthermore, combination therapy with bax gene transfer and subcutaneous administration of CDDP at 3-day intervals markedly inhibited the growth of mouse SCC. Thus, overexpression of bax in SCC by a gene gun system appears to be a rational approach to improving the efficacy of chemotherapy and treatment outcome. We suggest that exogenous bax expression may have therapeutic applications for enhancing chemotherapy in SCC.

Animals↗

PubMed1999

Evaluation of a cDNA scanning method concerning the fidelity and efficiency of cDNA selection using the YAC CIC3B1-S region of Arabidopsis thaliana chromosome 5.

We previously reported a cDNA selection method using DNA latex particles to identify expressed genes in specific regions of genomes and named this cDNA scanning method (Hayashida et al., 1995 Gene 155 161). We applied the cDNA scanning method to the YAC CIC3B1-S DNA on Arabidopsis thaliana chromosome 5, and constructed a region-specific sublibrary in which cDNAs for genes on the YAC CIC3B1-S DNA were concentrated. We isolated 545 cDNA clones from the sublibrary, and determined partial sequence of them to produce expressed sequence tags (ESTs) derived from the YAC region. In total, 74 nonredundant groups of cDNAs were obtained from 545 cDNA clones. Forty-seven percent of these EST clones had significant homology to functional proteins such as protein kinases, LON protease, nucleic acid binding protein and chloride channel protein. We compared the cDNA sequences isolated by the cDNA scanning method to the Arabidopsis genomic sequence corresponding to the YAC CIC3B1-S region, and found that 69% of the selected cDNAs are located in the region. We discuss the fidelity and efficiency of the cDNA scanning method for cloning region-specific cDNAs and its useful application in positional cloning.

Arabidopsis↗

PubMed1999

Evidence for the collateral innervation of the esophagus and the heart from neurons in the compact formation of the nucleus ambiguus of the rat.

We investigated whether the heart receives collateral projections from the neurons which innervate the esophagus with a retrograde double-labeling method using two fluorescent tracers. Following injections of True Blue (TB) into the esophagus and Diamidino Yellow (DY) into the heart, about 21.9% of the labeled esophageal motoneurons in the compact formation of the nucleus ambiguus (AmC) were retrogradely double labeled. No single-labeled cardiac motoneurons were found in the AmC. The present results provide anatomical substrates for the esophagocardiac reflex.

Amidines↗

PubMed1999

DNA replication errors produced by the replicative apparatus of Escherichia coli.

It has been hard to detect forward mutations generated during DNA synthesis in vitro by replicative DNA polymerases, because of their extremely high fidelity and a high background level of pre-existing mutations in the single-stranded template DNA used. Using the oriC plasmid DNA replication in vitro system and the rpsL forward mutation assay, we examined the fidelity of DNA replication catalyzed by the replicative apparatus of Escherichia coli. Upon DNA synthesis by the fully reconstituted system, the frequency of rpsL-mutations in the product DNA was increased to 1.9x10(-4), 50-fold higher than the background level of the template DNA. Among the mutations generated in vitro, single-base frameshifts predominated and occurred with a pattern similar to those induced in mismatch-repair deficient E. coli cells, indicating that the major replication error was slippage at runs of the same nucleotide. Large deletions and other structural alterations of DNA appeared to be induced also during the action of the replicative apparatus.

Base Pairing↗

PubMed1999

Direct parabrachial nuclear projections to the pharyngeal motoneurons in the rat: an anterograde and retrograde double-labeling study.

The parabrachial nucleus consists of several subnuclei which contains autonomic, gustatory, visceral sensory, nociceptive, and respiratory related neurons. We have investigated the direct projections from the rat parabrachial region, including the K olliker-Fuse nucleus, to the pharyngeal motoneurons with an anterograde and retrograde double-tracing technique. The cholera toxin subunit-B was injected into the lower pharynx or the esophagus after injection of biotinylated dextran amine into the ventrolateral parabrachial nuclear region, including the external medial, the external lateral, and the crescent area of the central lateral parabrachial nuclei and into the Kölliker-Fuse nucleus. The anterogradely dextran amine-labeled fibers from these nuclei projected to the semicompact, loose and external formations besides the compact formation of the nucleus ambiguus. Many anterogradely labeled fibers and terminals were found to contact retrogradely cholera toxin-labeled pharyngeal neuronal soma and dendrites in the semicompact formation of the nucleus ambiguus. The medial half of the parabrachial nucleus, including the medial and the medial part of the central lateral parabrachial nuclei, sent a few fibers to the reticular formation just dorsal to the esophageal motoneurons but no fibers to either the pharyngeal or to the esophageal motoneurons. These results suggested that the visceral sensory, gustatory, nociceptive or respiratory related neurons in the parabrachial nucleus project directly to the pharyngeal motoneurons, but there are no parabrachial projections to the esophageal motoneurons in the nucleus ambiguus.

Animals↗

PubMed1999

Inhibition of N-linked glycosylation by tunicamycin enhances sensitivity to cisplatin in human head-and-neck carcinoma cells.

Tunicamycin (TM), a naturally occurring antibiotic, blocks the first step in the biosynthesis of N-linked oligosaccharides in cells. In this study, we investigated whether changes in N-linked glycosylation affect the sensitivity of head-and-neck carcinoma cell lines to cis-diaminedichloroplatinum(II) (cisplatin) in vitro and in vivo. In vitro treatment of the IMC-3 and KB cell lines with TM significantly decreased the 50% inhibitory concentration (IC50) of cisplatin, as determined by the MTT assay (24.15 to 10.97 microg/ml, p < 0.05). In addition, TM significantly decreased the IC50 of cisplatin against established cisplatin-resistant IMC-3/CR cells (>100 to 14.4 microg/ml, p < 0.05) to levels similar to those against parental IMC-3 cells. TM treatment decreased the number of Con A- and L-PHA-binding sites on the surface of tumor cells but had no effect on the intracellular platinum concentration. Induction of apoptosis in vitro by TM plus cisplatin in combination was increased compared with that by cisplatin alone. Furthermore, in vivo administration of TM plus cisplatin in combination significantly inhibited local tumor growth in the cisplatin-resistant in vivo C3H/He mouse model as compared with the control group (p < 0.05) and increased in vivo apoptosis of tumor cells. Our results suggest that the manipulation of glycosylation by TM in tumor cells might be a useful therapeutic strategy for successful chemotherapy using cisplatin against head-and-neck cancer.

Animals↗

PubMed1999

Effect of olprinone, a phosphodiesterase III inhibitor, on arterial wall distensibility: differentiation between aorta and common carotid artery.

Although the effects of phosphodiesterase III (PDE III) inhibitors as vasorelaxants have been well documented, there are only few data on the wall response of different arteries. We evaluated the artery-specific effect of olprinone (OP), one of the PDE III inhibitors, on the major branches of human arteries and peripheral circulation. In 14 healthy subjects (average age: 57.5 +/- 21.2 years), systolic and diastolic diameters (Ds and Dd, respectively) and the time velocity integral (VI) of flow velocity patterns were measured by M-mode and Doppler echocardiography in the carotid artery (CA), the ascending aorta (asAo), the abdominal aorta (abAo), and the left ventricular outflow tract. Blood pressure (BP) was simultaneously measured using a cuff sphygmomanometer. Measurements were taken before and 20min after a bolus injection of OP (0.2 microg/kg). Distensibility (Ds - Dd), stiffness parameter beta (In(systolic BP/diastolic BP)/(Ds/Dd - 1)), cardiac output (CO: (Flow Area) x VI x HR at left ventricular outflow), selective flow volume (FV: (Flow Area) x VI x HR at CA or abAo), and vascular resistance (VR: mean BP/(CO or FV)) were then calculated. The distensibility increased significantly after OP administration (P = 0.0015), but that of the asAo or abAo did not change. Although there was a significant increase in CO (P = 0.001) and a significant decrease in systemic VR (P = 0.001) following OP administration, the FV and VR of both CA and abAo did not change significantly. The selectiveness of the effect of OP was demonstrated in terms of the CA wall distensibility. This was thought to be attributable to the differences in the structural components or the reactivity of smooth muscle cells to OP.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1999

Hepatic lymph node involvement in resected cases of liver metastases from colorectal cancer.

PURPOSE: Lymph node metastasis in the hepatoduodenal ligament is known as one of the most significant prognostic factors after liver resection for colorectal metastasis. However, there have been very few articles on the clinical features of node-positive patients and on detailed distribution of positive nodes. Further, there has been no established strategy on how to handle hepatic lymph nodes during liver resection. To address these subjects, a retrospective study was conducted. METHODS: During the period of 1980 through April 1998, 182 hepatic resections were performed for metastatic colorectal carcinoma. Of these, 78 cases had hepatic lymph node sampling during the operation. Distribution of positive nodes, location of liver metastasis, stage of the primary lesion, and outcome after liver resection were analyzed. RESULTS: Nine cases (12 percent) had secondary lymph node metastases in the hepatoduodenal ligament. The incidence was slightly higher (13.5 percent) in the most recent 44 consecutive cases. There was a tendency for liver metastases in the right lobe to metastasize to No. 12b (or node of the foramen of Winslow, lymph nodes along the common bile duct) and liver metastases in the left lobe to metastasize to No. 8a (anterosuperior group of the lymph nodes along the common hepatic artery). Outcome of node-positive patients (n = 9) was extremely poor (P < 0.001) compared with that of node-negative patients (n = 66), and the most common site of recurrence in the node-positive patients was remnant liver and hepatic lymph nodes. Preoperatively, there were no significant predicting factors for positive hepatic lymph nodes. CONCLUSIONS: No. 8a and No. 12b nodes are principal nodes that should be palpated and sampled during liver resection to check the secondary lymphatic spread from liver metastases. Hepatic nodal involvement indicates the progression of disease beyond simple liver metastases and may not be the indication for simple surgical removal. Further study, including hepatoduodenal dissection and systemic adjuvant chemotherapy, may elucidate the survival benefit, if any, of liver resection in node-positive patients.

Case-Control Studies↗

PubMed1999

Transient expression of the beta-glucuronidase gene in tissues of Arabidopsis thaliana by bombardment-mediated transformation.

Particle bombardment has proved to be useful for the transformation of plants. We have previously reported successful transient expression of the beta-glucuronidase (GUS) gene in cultured plant cells and tissues and the stable transformation of various plants using a pneumatic particle gun. In this chapter, we describe transient expression of the GUS gene in Arabidopsis thaliana leaves and roots using the pneumatic particle gun.

Arabidopsis↗