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Biomedical subjects

A Naito

Publications and source records attributed to A Naito.

At least 19 recordsLinked to original sources
PubMed2006

Endovascular therapy for abdominal pseudoaneurysms: analysis from technical and clinical aspects.

PURPOSE: To clarify the factors of outcomes by endovascular therapy for abdominal pseudoaneurysm (PSA) from both technical and clinical aspects. MATERIAL AND METHODS: Sixteen patients with PSAs underwent embolization. Embolic methods were classified into two groups: proximal and distal embolization (PDE) and proximal embolization alone (PE). The patients were classified into four groups by shock index. Pre-embolization hemoglobin (Hb) level and decrease in Hb level were evaluated. Outcomes were classified into two groups: successful recovery and failure despite successful PSA embolization. RESULTS: There were no statistical differences in success, recurrence, and complication rate, and outcomes between the two embolic methods. There was a statistically significant correlation between the grades of shock indices and outcomes (P<0.05). There was no statistical difference between the Hb levels and outcomes. CONCLUSION: Outcomes were not dependent on the embolic methods. Shock index reflecting clinical status may be a simple predictor of outcome. PSA should therefore be treated by optimal embolic methods as quickly as possible to avoid rupture.

Abdomen↗
PubMed2006

Preoperative portal vein embolization with a mixture of gelatin sponge and iodized oil: efficacy and safety.

PURPOSE: To evaluate whether portal vein embolization (PVE) using a mixture of gelatin sponge (GS) pieces and iodized oil is safe and effective in inducing hypertrophy of the future liver remnants (FLR). MATERIAL AND METHODS: PVE was performed in 14 patients (eight male and six female, mean age 65 years, range 35-81 years) diagnosed with malignant liver tumor before surgery, whose FLR volumes were judged too small to allow for safe resection. Liver volume change, biochemical data change, complications related to PVE, and postoperative complications were retrospectively evaluated. RESULTS: PVE was successful in all patients, and there were no procedural complications. Absolute FLR volume and FLR/total liver volume (TLV) ratio increased by 102 cm3 and 8% (mean values), respectively. Planned hepatectomies were cancelled in three patients due to extrahepatic metastasis or bile duct infection. Five of the 11 patients (45%) who underwent hepatectomies had major postoperative complications. However, complications due to hepatic failure were not seen. In 10 patients, except one whose outcome was fatal outcome, the mean hospitalization days with and without major complications were 73 and 33 days, respectively. CONCLUSION: PVE using a mixture of GS and iodized oil seems to be effective and safe in inducing hypertrophy of the FLR.

Adult↗
PubMed2006

Hospital nurse administrators in Japan: a feminist dimensional analysis.

BACKGROUND: Nursing administration research is scarce in Japan during a time when health care is rapidly reforming and baccalaureate and graduate nursing programmes are rapidly developing. Additionally, nursing administration content relies heavily on Western and non-nursing theories, some of which have been criticized for male bias. PURPOSE: The purpose of this article is to present key findings from a qualitative study that explored the perspectives or viewpoints of 16 Japanese senior female nurse administrators in hospitals in order to learn what was happening in their working situations and how they were managing. DESIGN AND METHODS: This feminist study used dimensional analysis strategies for data collection and analysis. Semi-structured, tape-recorded interviews were conducted by both researchers in Japanese, transcribed into Japanese, and translated into English. RESULTS AND DISCUSSION: The resulting explanatory matrix portrayed a story of 16 nurse administrators, most of whom were able successfully to enact a management role in a context of role ambiguity that was congruent with their relational values and beliefs. Important conditions influencing value-based role enactment included organization mission and purpose, organization structure, nurse-doctor relationships, participant-supervisor relationships, and personal attributes. Many participants were able to overcome barriers in these categories using strategies of tempered radicalism and consequently made positive organizational changes. CONCLUSIONS: Advanced formal education, better organizational support, and a raised consciousness among nurses that views nurses and midwives as equal partners with other professionals will enable Japanese nurse administrators to help advance patient-centred care and nursing development and empowerment.

Adaptation, Psychological↗
PubMed2003

Morphologic and histopathologic changes in the bowel after super-selective transcatheter embolization for focal lower gastrointestinal hemorrhage.

PURPOSE: To evaluate the safety of superselective arterial embolization therapy in the lower gastrointestinal tract. The sequelae on normal enteric tissue in lower gastrointestinal arterial embolization were retrospectively reviewed. MATERIAL AND METHODS: To control hemorrhage and tumor blood supply, 14 patients were treated by superselective transcatheter embolization at different levels of the colonic and small intestine vessels via the superior and inferior mesenteric arteries using microcoils and/or gelatin sponge. Normal enteric tissues in the embolized areas were analyzed for the occurrence of ischemic changes by clinical follow-up, colonoscopy, and surgery. RESULTS: Normal bowel function was preserved in 13 patients. In 1 patient treated with numerous gelatin sponge particles delivered from the proximal arcade of the superior mesenteric artery, significant muscular fibrosis occurred. CONCLUSION: Superselective arterial embolization for lower gastrointestinal hemorrhage can be safely performed by minimizing the amount of embolic materials and delivering them as distally as possible.

Colon↗
PubMed2002

A motion of forearm supination with maintenance of elbow flexion produced by electrical stimulation to two elbow flexors in humans.

Motions of the forearm induced by electrical stimulation to two elbow flexors (brachioradialis: BR, biceps brachii: BB) were examined in five healthy human subjects. Stainless steel wire electrodes were implanted percutaneously into each motor point of the muscles. The muscles were stimulated separately with a computer-controlled multi-channel stimulator. The motions were taken with a digital video system. Angular changes of the motions in elbow flexion/extension and forearm pronation/supination were measured. Electromyograms (EMG) of BR, BB, and the triceps brachii (TB) were recorded. Electrical stimulation to BR induced a motion of flexion and that to BB motions of flexion and supination. The stimulation to BR with an adequate intensity provided holding of flexion with the prone forearm in all the subjects. In this situation, additional stimulation to BB resulted in motions of flexion and supination. However, the additional stimulation accompanied with a decrease of the stimulation intensity for BR provided a motion of supination with maintenance of the flexion in all the subjects. Since during the stimulation BR, BB, and TB showed no voluntary contraction in EMG, it is suggested that modulation of contraction between BR and BB by the stimulation can produce force in supination with keeping constant force in flexion to support the weight below the elbow.

Adult↗
PubMed2002

Evaluation of 5-S-cysteinyldopa as a marker of melanoma progression: 10 years' experience.

5-S-Cysteinyldopa (5-S-CD) has been used as a biochemical marker of melanoma progression. In this study, we measured serum levels of 5-S-CD in 2648 samples taken from 218 patients in order to evaluate the usefulness of this parameter in following melanoma progression and prognosis. 5-S-CD levels were significantly elevated above the upper limit of the normal range (10 nmol/l) in stage IV melanoma patients. The sensitivity of elevated serum 5-S-CD levels in detecting distant metastasis was 73%, while the specificity was 98% and the positive predictive value 94%. The sensitivity was improved to 77% when cases of amelanotic melanoma were excluded. Patients without metastases had elevated 5-S-CD values in 5% of the 1480 serum samples. Changes in serum 5-S-CD levels were followed during disease progression until the end stage in 49 patients. In 33% of the patients, elevation of serum 5-S-CD levels preceded clinical detection of visceral metastases, and in 37% elevation of 5-S-CD levels occurred at the same time as visceral metastasis. Patients with elevated 5-S-CD levels before or after surgical treatment had significantly shorter survival times than those with normal levels. These results show that the level of 5-S-CD in the serum is a sensitive and specific marker in predicting distant metastases. Elevated serum levels of 5-S-CD, before or after surgical treatment, is associated with a poor prognosis.

Adolescent↗
PubMed2001

Annexin II overexpression correlates with stromal tenascin-C overexpression: a prognostic marker in colorectal carcinoma.

BACKGROUND: Overexpression of annexin II, a calcium-dependent phospholipid-binding protein, has been reported in various carcinomas. One of its ligands is tenascin-C, an extracellular matrix glycoprotein with predominantly antiadhesive qualities that also has been reported to be a prognostic marker for several carcinomas. In the current study, the authors investigated the correlation between the overexpression of annexin II and tenascin-C in colorectal carcinoma. METHODS: Western blot analysis of annexin II expression was examined in four human colorectal carcinoma cell lines. Using immunohistochemical methods, the authors also examined expression of annexin II and tenascin-C in 105 primary colorectal carcinoma cases. RESULTS: Although annexin II was expressed in human colon carcinoma cell lines, there was no apparent correlation between its expression level and the metastatic potential of these cell lines. The authors observed overexpression of annexin II and tenascin-C proteins in 29.5% and 49.5%, respectively, of colorectal carcinoma cases. Overexpression of annexin II was found to be correlated significantly with histologic type, tumor size, depth of invasion, and pTNM stage, whereas tenascin-C overexpression was noted to be correlated significantly with histologic type, depth of invasion, lymphatic invasion, venous invasion, lymph node metastasis, and pTNM stage. Expression of annexin II was shown to be correlated significantly with that of tenascin-C. Multivariate analysis demonstrated that annexin II and tenascin-C cooverexpression was an independent factor of poor prognosis in patients with colorectal carcinoma. CONCLUSIONS: The data from the current study suggest that both annexin II and tenascin-C are overexpressed in advanced colorectal carcinoma and that they may be related to the progression and metastatic spread of colorectal carcinoma.

Annexin A2↗
PubMed2001

High susceptibility of transgenic rats carrying the human c-Ha-ras proto-oncogene to chemically-induced mammary carcinogenesis.

A rat line carrying three copies of the human c-Ha-ras proto-oncogenes, including its own promoter region, was established and designated as Hras128. Expression of the transgene was detected in all organs by Northern blot analysis. To examine its influence on susceptibility to mammary carcinogenesis, female rats were treated with N-methyl-N-nitrosourea (MNU) or 7,12-dimethylbenz[a]anthracene (DMBA) at 50 days of age. With MNU, all the transgenic rats rapidly developed multiple mammary carcinomas within as short as 8 weeks (14.1 tumors/rat), in contrast to 0.46 tumors/rat in non-transgenic rats. PCR-RFLP analysis and direct sequencing for the transgene indicated that the large majority of carcinomas (38/44, 86.4%) contained cells with mutations at codon 12 in exon 1. However, comparison of the signal densities of the mutated band to dilution scale bands revealed that the cells with the mutated transgene were not in the majority. By PCR-SSCP analysis for codons 12 and 61 of the rat endogenous c-Ha-ras gene, no mutations were detected. Similarly, with DMBA, almost all (13/14, 92.9%) the transgenic rats developed multiple mammary carcinomas (9.39 tumors/rat) within 16 weeks, and 4 out of 12 (33.3%) non-transgenic rats had only small tumors (0.83 tumors/rat). A lower incidence of mutation of the transgene was found in codon 12 (5/25, 25%) than in MNU-induced tumors, but mutations were detected in codon 61 (7/20, 35%). No mutations were detected in the rat endogenous gene. No mutation was found in the rat endogenous c-Ha-ras gene in non-transgenic rats. As observed in both the MNU- and DMBA-induced tumor cases, the population of cells with the mutated transgene were in the minority. The results thus indicate that rats carrying the transduced human c-Ha-ras proto-oncogene are highly susceptible to MNU- and DMBA-induced mammary carcinogenesis and that this is not primarily due to mutations of the transgene or endogenous c-Ha-ras gene. Furthermore, irrespective of the mechanism of enhanced susceptibility, the Hras128 transgenic rats can be utilized for the screening of mammary carcinogens.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2001

Segregation of TRAF6-mediated signaling pathways clarifies its role in osteoclastogenesis.

Signals emanating from the receptor for interleukin-1 (IL-1), lipopolysaccharide (LPS) or osteoclast differentiation factor/receptor activator of NF kappa B ligand (ODF/RANKL) stimulate transcription factors AP-1 through mitogen-activated protein kinase (MAPK) activation and NF kappa B through I kappa B kinase (IKK) activation. These kinases are thought to be activated by tumor necrosis factor receptor-associated factor 6 (TRAF6). However, molecular mechanisms by which TRAF6 activates various downstream kinases remain to be elucidated. We identified functional domains of TRAF6 under physiological conditions established by appropriate expression of TRAF6 mutants in TRAF6-deficient cells. In IL-1 and LPS signaling pathways, the RING finger and first zinc finger domains are not required for NF kappa B activation but are required for full activation of MAPK. However, IL-1 and LPS signals utilize distinct regions within the zinc finger domains of TRAF6 to activate NF kappa B. Furthermore, the RING finger domain is not required for differentiation of splenocytes to multinuclear osteoclasts, but is essential for osteoclast maturation. Thus, TRAF6 plays essential roles in both the differentiation and maturation of osteoclasts by activating various kinases via its multiple domains.

Animals↗
PubMed2001

Global effects of anchorage on gene expression during mammary carcinoma cell growth reveal role of tumor necrosis factor-related apoptosis-inducing ligand in anoikis.

Anchorage-independent growth is a hallmark of tumor cells. We compared gene expression profiles of anchored and nonanchored human mammary carcinoma cells to study this phenomenon. In this study, we show that anchorage had striking effects on cell growth and morphology but altered transcript levels from a limited number of genes. Only about 1% of mRNA transcripts detected in these cells was altered by anchorage. These include genes related to amino acid and polyamine metabolism, apoptosis, ion channels, cytoskeletal and stress proteins, transcription factors, and growth factors. Some of these may be crucial for the survival of transformed cells. For example, clusterin and the tumor necrosis factor-related apoptosis inducing ligand (TRAIL) were suppressed by anchorage, which could help prevent programmed cell death of these tumor cells. In addition to suppressing TRAIL expression, anchorage also decreased the susceptibility of these tumor cells to TRAIL-induced apoptosis as determined by poly(ADP-ribose) phosphorylase cleavage, annexin-V binding (P < 0.01), and cell cycle analysis (P < 0.0001). These data may help explain mechanisms by which anchorage prevents apoptosis of cells that would otherwise experience anoikis. Thus, genes found to be altered by this analysis could serve as potential targets for anticancer therapy. These findings suggest that TRAIL may be used as a means to target circulating epithelial tumor cells before their attachment and colonization at new sites.

Anoikis↗
PubMed2001

A (13)C NMR study on [3-(13)C]-, [1-(13)C]Ala-, or [1-(13)C]Val-labeled transmembrane peptides of bacteriorhodopsin in lipid bilayers: insertion, rigid-body motions, and local conformational fluctuations at ambient temperature.

We have recorded (13)C NMR spectra of selectively [3-(13)C]Ala-, [1-(13)C]Ala-, or [1-(13)C]Val-labeled synthetic transmembrane peptides of bacteriorhodopsin (bR) and enzymatically cleaved C-2 fragment in the solid and dimyristoylphosphatidylcholine bilayer. It turned out that these transmembrane peptides either in hexafluoroisopropanol or cast from it take an ordinary alpha-helix (alpha(I)-helix) irrespective of their amino acid sequences with reference to the conformation-dependent (13)C chemical shifts of (Ala)(n) taking the alpha-helix form. These transmembrane peptides are not always static in the lipid bilayer as in the solid state but undergo rigid-body motions with various frequencies as estimated from suppressed peaks either by fast isotropic or large-amplitude motions (>10(8) Hz) or intermediate frequencies (10(5) or 10(3) Hz). Further, (13)C chemical shifts of the [3-(13)C]Ala-labeled peptides in the bilayer were displaced downfield by 0.3-1.1 ppm depending upon amino acid sequence with respect to those in the solid state, which were explained in terms of local conformational fluctuation (10(2) Hz) deviated from the torsion angles (alpha(II)-helix) from those of standard alpha-helix, under anisotropic environment in lipid bilayer, in addition to the above-mentioned rigid-body motions. The carbonyl (13)C peaks, on the other hand, are not sensitively displaced by such local anisotropic fluctuations, because they are more sensitive to the manner of hydrogen-bond interactions. The amino acid sequences of these peptides inserted within the bilayer were not always the same as those of intact bR, causing disposition of the transmembrane alpha-helical segment from that of intact bR. Finally, we confirmed that the (13)C NMR peak positions of the random coil form are located at the boundary between the alpha-helix and a turned structure in loop regions.

Alanine↗
PubMed2001

Clinical significance of E-cadherin expression in thyroid neoplasms.

BACKGROUND AND OBJECTIVE: E-cadherin, a calcium-dependent transmembrane glycoprotein, is an adhesion molecule. We studied clinical significance of E-cadherin expression in thyroid neoplasms. METHODS: We immunohistochemically studied E-cadherin expression in 60 normal tissue specimens of thyroid tissues and in 82 follicular adenomas, 53 papillary carcinomas, 4 follicular carcinomas, 2 medullary carcinomas, and 5 anaplastic carcinomas of the thyroid. RESULTS: In papillary carcinoma, E-cadherin expression was preserved significantly less often than in follicular adenoma or normal thyroid tissue (P < 0.01). Preserved E-cadherin expression was seen less often among papillary carcinomas with lymph node metastasis than in those without metastasis (P < 0.05). CONCLUSIONS: This loss of E-cadherin expression may be involved in regional lymph node metastasis and in malignant potential of thyroid neoplasms. J. Surg. Oncol. 2001;76:176-180.

Adenocarcinoma, Follicular↗
PubMed2001

Regio-selective detection of dynamic structure of transmembrane alpha-helices as revealed from (13)C NMR spectra of [3-13C]Ala-labeled bacteriorhodopsin in the presence of Mn2+ ion.

13C Nuclear magnetic resonance (NMR) spectra of [3-(13)C]Ala-labeled bacteriorhodopsin (bR) were edited to give rise to regio-selective signals from hydrophobic transmembrane alpha-helices by using NMR relaxation reagent, Mn(2+) ion. As a result of selective suppression of (13)C NMR signals from the surfaces in the presence of Mn(2+) ions, several (13)C NMR signals of Ala residues in the transmembrane alpha-helices were identified on the basis of site-directed mutagenesis without overlaps from (13)C NMR signals of residues located near the bilayer surfaces. The upper bound of the interatomic distances between (13)C nucleus in bR and Mn(2+) ions bound to the hydrophilic surface to cause suppressed peaks by the presence of Mn(2+) ion was estimated as 8.7 A to result in the signal broadening to 100 Hz and consistent with the data based on experimental finding. The Ala C(beta) (13)C NMR peaks corresponding to Ala-51, Ala-53, Ala-81, Ala-84, and Ala-215 located around the extracellular half of the proton channel and Ala-184 located at the kink in the helix F were successfully identified on the basis of (13)C NMR spectra of bR in the presence of Mn(2+) ion and site-directed replacement of Ala by Gly or Val. Utilizing these peaks as probes to observe local structure in the transmembrane alpha-helices, dynamic conformation of the extracellular half of bR at ambient temperature was examined, and the local structures of Ala-215 and 184 were compared with those elucidated at low temperature. Conformational changes in the transmembrane alpha-helices induced in D85N and E204Q and its long-range transmission from the proton release site to the site around the Schiff base in E204Q were also examined.

Alanine↗
PubMed2001

Cytoplasmic surface structure of bacteriorhodopsin consisting of interhelical loops and C-terminal alpha helix, modified by a variety of environmental factors as studied by (13)C-NMR.

We have examined the (13)C-NMR spectra of [3-(13)C] Ala-labeled bacteriorhodopsin and its mutants by varying a variety of environmental or intrinsic factors such as ionic strength, temperature, pH, truncation of the C-terminal alpha helix, and site-directed mutation at cytoplasmic loops, in order to gain insight into a plausible surface structure arising from the C-terminal alpha helix and loops. It is found that the surface structure can be characterized as a complex stabilized by salt bridges or metal-mediated linkages among charged side chains. The surface complex in bacteriorhodopsin is most pronounced under the conditions of 10 mM NaCl at neutral pH but is destabilized to yield relaxed states when environmental factors are changed to high ionic strength, low pH and higher temperature. These two states were readily distinguished by associated spectral changes, including suppressed (cross polarization-magic angle spinning NMR) or displaced (upfield) (13)C signals from the C-terminal alpha helix, or modified spectral features in the loop region. It is also noteworthy that such spectral changes, when going from the complexed to relaxed states, occur either when the C-terminal alpha helix is deleted or site-directed mutations were introduced at a cytoplasmic loop. These observations clearly emphasize that organization of the cytoplasmic surface complex is important in the stabilization of the three-dimensional structure at ambient temperature, and subsequently plays an essential role in biological functions.

Amino Acid Sequence↗
PubMed2001

Surface dynamics of bacteriorhodopsin as revealed by (13)C NMR studies on [(13)C]Ala-labeled proteins: detection of millisecond or microsecond motions in interhelical loops and C-terminal alpha-helix.

We have recorded (13)C NMR spectra of [2-(13)C]-, [1-(13)C]-, [3-(13)C],- and [1,2,3-(13)C(3)]Ala-labeled bacteriorhodopsin (bR), and its mutants, A196G, A160G, and A103C, by means of cross polarization-magic angle spinning (CP-MAS) and dipolar decoupled-magic angle spinning (DD-MAS) techniques, to reveal the conformation and dynamics of bR, with emphasis on the loop and C-terminus structures. The (13)C NMR signals of the loop (C-D, E-F, and F-G) regions were almost completely suppressed from [2-(13)C]-, [1-(13)C]Ala-, and [1-(13)C]Gly-labeled bR, due to the presence of conformational fluctuation with correlation times of 10(-4) s that interfered with the peak-narrowing by magic angle spinning. The observation of such suppressed peaks for specific residues provides a unique means of detecting intermediate frequency motions on the time scale of ms or micros in the surface loops of membrane proteins. Instead, the three well-resolved (13)C CP-MAS NMR signals of [2-(13)C]Ala-bR, at 50.38, 49.90, and 47.96 ppm, were ascribed to the C-terminal alpha-helix previously proposed from the data for [3-(13)C]Ala-bR: the former two peaks were assigned to Ala 232 and 238, in view of the results of successive proteolysis experiments, while the highest-field peak was ascribed to Ala 235 prior to Pro 236. Even such (13)C NMR signals were substantially broadened when (13)C NMR spectra of fully labeled [1,2,3-(13)C]Ala-bR were recorded, because the broadening and splitting of peaks due to the accelerated transverse relaxation rate caused by the increased number of relaxation pathways through a number of (13)C-(13)C homo-nuclear dipolar interactions and scalar J couplings, respectively, are dominant among (13)C-labeled nuclei. In addition, approximate correlation times for local conformational fluctuations of different domains, including the C-terminal tail, C-terminal alpha-helix, loops, and transmembrane alpha-helices, were estimated by measurement of the spin-lattice relaxation times in the laboratory frame and spin-spin relaxation times under the conditions of cross-polarization-magic angle spinning, and comparative study of suppressed specific peaks between the CP-MAS and DD-MAS experiments.

Alanine↗