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Biomedical subjects

S Iijima

Publications and source records attributed to S Iijima.

At least 37 records · Page 2Linked to original sources
PubMed2001

Expression of chromatin remodeling factors during neural differentiation.

The yeast SWI/SNF complex is involved in remodeling of chromatin structure during transcriptional modulation. One of the key subunits of this complex, called SWI2/SNF2, has a DNA-dependent ATPase activity. Two different types of mammalian homolog of yeast SWI2/SNF2, called BRM and BRG1, were recently identified. They are closely similar in structure but have distinct functions. We investigated the expression of BRM and BRG1 during differentiation of neural precursor cells (NPCs) cultured in vitro. The expression of BRM was very low in NPCs and was induced to a high level during differentiation to neurons and astrocytes. In contrast, BRG1 was constantly expressed throughout differentiation. These phenomena were also observed in differentiation of P19 embryonal carcinoma cells to neural cells. Immunocytochemical analyses revealed that the expression of BRM started even in the undifferentiated nestin-positive cells. These results indicate that BRM may have an important role in neural cell differentiation.

Cell Differentiation↗
PubMed2001

[Structural quantification of bone from radiographs using power spectral analysis].

Bone mineral density (BMD) and bone structure are very important indices for prevention of fracture. However, it is very difficult to quantify bone structure, and only a few indices for structural quantification of bone have been reported. The purpose of this research was to investigate a new index for bone structure. The subjects were 52 women aged from 20 to 85 years. Directivity index (DI) is a new index of bone structure calculated by directivity of power spectrum from radiographs of metacarpal bone using fast Fourier transform (FFT). DI was obtained by subtracting the integral power value at 0 and 90 degree directions on the x-y plane of the two-dimensional power spectrum of bone from the integral power value at a direction of 45 degrees. A significant relationship between BMD and DI was indicated by correlation coefficient. However, no significant relationship between BMD and the first moment of the Fourier power spectrum or the fractal dimension was found. There is a possibility that DI estimates a slight deformation of bone structure. In the future, we will apply DI to the prevention of fractures and osteoarthritis.

Adult↗
PubMed2001

[The new portable system for home enteral nutrition, Portermate, made a patient possible go out for a long time: report of a case].

The patient, who is received home enteral nutrition (HEN) for a long time in a day, has problems on moving all days. Now, we tried Portermate, which is new portable devices for HEN, in his clinical care. The patient is chronic pancreatitis, and his clinical problems becomes to be worse after he ate. He was under total enteral nutrition via jejunostomy. His clinical complications were almost controlled after HEN, but he has a few complains receiving enteral nutrition. He would not move easily, for an old HEN system was not compact to move. Portermate made him go everywhere he wanted any time. It extremely improved his QOL under HEN. He continues to use Portermate.

Activities of Daily Living↗
PubMed2000

Element-selective single atom imaging.

Electron energy-loss spectroscopy (EELS) is widely used to identify elemental compositions of materials studied by microscopy. We demonstrate that the sensitivity and spatial resolution of EELS can be extended to the single-atom limit. A chemical map for gadolinium (Gd) clearly reveals the distribution of Gd atoms inside a single chain of metallofullerene molecules (Gd@C82) generated within a single-wall carbon nanotube. This characterization technique thus provides the "eyes" to see and identify individual atoms in nanostructures. It is likely to find broad application in nanoscale science and technology research.

Journal Article↗
PubMed2000

One-dimensional metallofullerene crystal generated inside single-walled carbon nanotubes.

Electron microscope imaging for gadolinium metallofullerenes encapsulating in single-wall carbon nanotubes [(Gd@C82)n@SWNTs] identifies the single Gd atom encaged in each. The intermolecular distance between Gd@C82 is extremely regular, regarding the chains of Gd@C82 as novel one-dimensional crystals. Chemical state analysis of Gd atoms suggests evidence for charge transfer from Gd to either a fullerene cage or a nanotube. The slopes of the temperature dependence of electric resistance for the mat-like films of (Gd@C82)n@SWNTs and (C60)n@SWNTs are much steeper than that for empty SWNTs, suggesting the electron scattering due to the electrostatic potential from inside fullerenes playing an important role.

Journal Article↗
PubMed2000

Compressibility and polygonization of single-walled carbon nanotubes under hydrostatic pressure

Single-walled carbon nanotubes show linear elasticity under hydrostatic pressure up to 1.5 GPa at room temperature. The volume compressibility, measured by in situ synchrotron x-ray diffraction, has been determined to be 0.024 GPa (-1). Theoretical calculations suggest that single-walled carbon nanotubes are polygonized when they form bundles of hexagonal close-packed structure and the intertubular gap is smaller than the equilibrium spacing of graphite (002) (d = 3.35 A). It has also been determined that the deformation of the trigonal nanotube lattice under hydrostatic pressure is reversible up to 4 GPa, beyond which the nanotube lattice is destroyed.

Journal Article↗
PubMed2000

An alternative method of arterial reconstruction after hepatic arterial thrombosis following living-related liver transplantation.

BACKGROUND: Hepatic artery thrombosis (HAT) remains an important cause of graft loss after liver transplantation. Emergency rearterialization methods are limited in cases of living-related liver transplantation in which the graft hepatic artery is thin and short. CASE: A 19-year-old woman who underwent living-related liver transplantation for biliary atresia developed HAT on the 4th postoperative day. During the emergency laparotomy the recipient hepatic artery was found to be too short to anastomose, so the recipient's right gastroepiploic artery was anastomosed to the graft hepatic artery. The patient is now alive and well 6 months after reoperation, and she has experienced no further episode of HAT. CONCLUSION: The right gastroepiploic artery can be used easily and safely for hepatic graft revascularization without causing ischemia of the stomach. An additional skin incision is not required, and the artery is long enough to anastomose to the graft artery directly. The method of hepatic graft rearterialization described here is an important option for patients who undergo living-related or split liver transplantation.

Adult↗
PubMed2000

Structure and function of a novel coliphage-associated sialidase.

A coliphage named 63D, isolated previously, associated sialidase as a component of phage particles. In order to localize the enzyme in phage particles, phages were partially destroyed by sonication, and the disrupted particles were size fractionated using a sucrose density gradient. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, enzyme assay and electron micrography of the fractions revealed the enzyme to be composed of four identical subunits with a molecular mass of 90 kDa, and the subunits were cross-linked by disulfide bonds. Electron micrographic observation indicated that six enzyme molecules were localized in a phage tail plate as a hexagonal array.

Cell Fractionation↗
PubMed2000

Changes of alpha1-acid glycoprotein microheterogeneity in acute inflammation stages analyzed by isoelectric focusing using serum obtained postoperatively.

The relationship between variations of alpha1-acid glycoprotein (orosomucoid, AGP) microheterogeneity detected from isoelectric focusing (IEF) patterns and clinical stage of acute inflammation based on serum C-reactive protein (CRP) levels and interleukin-6 (IL-6) levels was investigated. Serum samples were obtained from healthy subjects, and from patients with esophageal or stomach carcinoma before and after operation. Samples without neuraminidase treatment were used for AGP microheterogeneity analysis, and samples with neuraminidase treatment for AGP heterogeneity analysis. In AGP microheterogeneity, nine bands were detected in the range of pI 3.18-3.57 in sera obtained from healthy subjects. In patients, AGP microheterogeneity changed the first day after operation; the percentage of bands surrounding pI 3.5 increased, and the highest value appeared in sera taken the first or second day after operation and then decreased quickly. These bands showed reactivity for concanavalin A (Con A). The increase in Con A-reactive AGP occurred later than the increase in IL-6, and occurred earlier than the increase in CRP. On the seventh day after operation, the percentage of bands around pI 3.2 increased. These bands showed the reactivity for Datura stramonium agglutinin. On the other hand, in samples with neuraminidase treatment, little change of AGP heterogeneity was observed in most samples, which did not reflect the stage of inflammation. These findings suggested that AGP microheterogeneity detection was a useful marker for the clinical stage of inflammation.

Aged↗
PubMed2000

Uterine myxoid leiomyosarcoma.

BACKGROUND: Uterine myxoid leiomyosarcoma is rare, has a poor prognosis, and must be distinguished from a uterine myoma with myxomatous change. CASE: A 56-year-old woman with a history of epigastric pain and generalized abdominal swelling had a peritoneal cavity filled with tumor that originated from the posterior uterine wall. Chemotherapy and two operations for recurrence could not prevent fatal metastases to the vascular system. Histopathology showed a typical myxoid leiomyosarcoma. CONCLUSION: Although the patient's prognosis was poor, no mitoses were observed, and the nuclear abnormalities were not sufficient to diagnose the tumor as malignant at the initial surgery. Whenever a uterine myoma with myxomatous change is found, the patient should be monitored carefully.

Fatal Outcome↗
PubMed2000

Molecular cloning and characterization of a novel bacteriophage-associated sialidase.

Bacteriophage 63D, previously isolated from sewage, is associated with alpha-2,8-linked polysialic acid degrading activity. We cloned a DNA fragment containing the sialidase gene from a 63D phage genomic library and the enzyme was functionally expressed in Escherichia coli. Determination of the nucleotide sequence of the fragment revealed that it contained one open reading frame (ORF) coding for a 108-kDa polypeptide consisting of 984 amino acid residues. The fragment had promoter sequences similar to the E. coli consensus promoters for sigma70. The deduced amino acid sequence of the central region of the ORF showed homology to those of phages K1F (51.6% identity) and PK1E (51.7% identity) endosialidases. Two Asp-box motifs that are widely found in sialidases were conserved. Purification of the soluble enzyme from lysed culture broth of infected E. coli yielded a 90-kDa protein upon SDS polyacrylamide gel electrophoresis, suggesting that the primary translational product is processed to the mature 90-kDa protein. The molecular mass of the enzyme was determined as 360 kDa by gel filtration, indicating that the native enzyme was probably a tetramer of identical 90-kDa subunits.

Journal Article↗
PubMed2000

Transcriptional regulation of nir and nor operons of Paracoccus denitrificans.

Transcripts of nitrite reductase (nir) and nitric oxide reductase (nor) operons of Paracoccus denitrificans were expressed only under anaerobic conditions in the presence of potassium nitrite. The nir and nor operons produced at least two transcription products. Large transcripts seemed to contain whole operons and small ones seemed to contain the genes encoding denitrifying enzymes. All transcription start sites were detected 41.5 or 42.5 bp downstream from the center of FNR boxes.

Journal Article↗
PubMed2000

Oral supplementation with gamma-linolenic acid extracted from Mucor circinelloides improves the deformability of red blood cells in hemodialysis patients.

BACKGROUND: The development of abnormalities in red blood cell (RBC) deformability in patients undergoing hemodialysis remains a major problem, because it is related to peripheral microcirculation, oxygen supply, and various complications in such patients. gamma-Linolenic acid (GLA; 18:3n-6), one of the polyunsaturated fatty acids and a precursor of prostaglandin E(1), is reported to have a favorable effect on the deformability of circulating blood cells in diabetic patients. METHODS: In order to clarify the efficacy of GLA on RBC deformability in 7 patients undergoing maintenance hemodialysis, we examined in a pilot study the changes in the deformability of RBC and the changes in the phospholipid fatty acid composition in both plasma and RBC membrane before and after high-dose oral supplementation with GLA derived from Mucor circinelloides for 12 weeks. RESULTS: Before supplementation, the micropore passage time of RBC suspension, which is an indicator of RBC deformability, in these patients was markedly longer than that in healthy control subjects. After administering GLA, the prolonged passage time of the patients both rapidly and steadily decreased and nearly reached control levels. Light microscopic observations of RBCs using Giemsa stain revealed a decreased number of poikilocytes after supplementation. An analysis of the fatty acid composition before treatment and 8 weeks after starting the treatment showed the dihomo-gamma-linolenic acid (DGLA; 20:3n-6) level in the plasma to have increased (p < 0.05), while the arachidonic acid (AA; 20:4n-6) concentration in the RBC membrane decreased (p < 0.05). The level of DGLA in the RBC membrane, the level of GLA, and the ratio of GLA + DGLA/AA in plasma and RBC membrane did not change significantly; however, these all tended to increase. CONCLUSION: The results of this pilot study indicate that the oral supplementation of GLA extracted from M. circinelloides improves the poor RBC deformability in hemodialysis patients, partly by inducing changes in the composition of fatty acids in plasma and RBC membrane.

Adult↗
PubMed2000

[SIRS in surgical stress].

It has been suggested that SIRS are triggered by superfluous pro-inflammatory cytokine production, and that organ injury is caused by uncontrolled inflammatory responses. However, the results of clinical studies, on the usefulness of specific cytokine antagonists and anti-TNF antibodies for the treatment of septic shock, have been unsatisfactory. The reason for this might have been that when uncontrolled inflammatory reactions progressed locally, anti-inflammatory reactions were elevated in the circulated blood by way of CARS, thus the timing of administration and pharmacokinetics did not match clinical course. Recent research has shown that SIRS is always accompanied by CARS, and since it seems to do the amplitude of SIRS and CARS to each other so that there may be a deep valley, if there is a high mountain. We introduce the recent knowledge which indicates that SIRS is a preliminary alert for not only organ dysfunction but also immunosuppression after severe injury or major surgery.

Cytokines↗
PubMed2000

[Enteral nutrition for gastrointestinal disease in home care].

We report 5 patients given enteral feeding in order to continue its nutritional supportive care of our hospital. In patients 1, 2, and 3 who were malnourished, enteral nutrition was provided due to poor oral intakes after surgical treatment. In patients 4 and 5, enteral feedings were made via the proximal jejunum in order to bypass the duodenum, for nutrients in the duodenum enhanced their biliary infection or chronic pancreatitis, respectively. All patients' nutritional status was satisfactory, but two of five patients could not be discharged from the hospital. The reason was that the patients and their families wanted to continue the hospital care in spite of the improvement in the clinical problem. They had no help at home to care for the patient. We conclude that enteral nutrition is very useful for gastrointestinal disease, but that social problems affect home care with enteral nutrition.

Aged↗
PubMed1999

Heterostructures of single-walled carbon nanotubes and carbide nanorods

A method based on a controlled solid-solid reaction was used to fabricate heterostructures between single-walled carbon nanotubes (SWCNTs) and nanorods or particles of silicon carbide and transition metal carbides. Characterization by high-resolution transmission electron microscopy and electron diffraction indicates that the heterostructures have well-defined crystalline interfaces. The SWCNT/carbide interface, with a nanometer-scale area defined by the cross section of a SWCNT bundle or of a single nanotube, represents the smallest heterojunction that can be achieved using carbon nanotubes, and it can be expected to play an important role in the future fabrication of hybrid nanodevices.

Journal Article↗