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Biomedical subjects

A Iwata

Publications and source records attributed to A Iwata.

At least 37 records · Page 2Linked to original sources
PubMed2000

A conditioning lesion promotes in vivo nerve regeneration in the contralateral sciatic nerve of rats.

A conditioning lesion in the sciatic nerve increases in vivo axonal regeneration in the nerve after a second transection. We studied whether this increased regeneration also occurs in the contralateral nerve. The left sciatic nerve was transected and sutured in Wistar rats; the nerve was exposed but not transected in controls. After 5 days, the right sciatic nerves of all rats were transected and sutured. Neuronal regeneration was measured at 0, 1, 3, 5, and 7 days with the pinch test and histological staining. IL-1beta and TGF-beta1 expression was also measured. The initial delay in the experimental group was significantly shorter, but the regeneration rates were the same. The expression of IL-1beta and TGF-beta1 in the right dorsal root ganglia was significantly higher in the experimental group. Nerve injury enhances cytokine expression in the contralateral dorsal root ganglion and promotes contralateral nerve regeneration in vivo by shortening the initial delay.

Animals↗
PubMed2000

Expression of canine interferon-beta by a recombinant vaccinia virus.

A recombinant vaccinia virus expressing canine interferon (IFN)-beta was constructed (vv/cIFN-beta). In rabbit kidney (RK13) and canine A72 cells infected with vv/cIFN-beta, the recombinant canine IFN-beta was detected in both cell extracts and supernatants, and the IFN activities of the culture supernatants were also detected. Inhibition of N-linked glycosylation by tunicamycin treatment indicated that the recombinant canine IFN-beta was modified by N-linked glycosylation in a different way between RK13 and A72 cells, and that N-linked glycosylation is essential for its secretion. The growth of vv/cIFN-beta at a low multiplicity of infection was inhibited by antiviral activity of canine IFN-beta, indicating that this recombinant virus could be used as a suicide viral vector.

Animals↗
PubMed2000

Evaluation of core decompression for early osteonecrosis of the femoral head.

Twenty-six hips (19 patients) with osteonecrosis of the femoral head with stage I or II of the disease, according to the Ficat and Arlet classification, underwent core decompression. Osteonecrosis was confirmed histologically in all 26 hips. Of 19 patients, 7 had prognostic factors traditionally associated with poor outcome including collagen vascular disease and continued use of steroids. The follow-up period averaged 7 years 10 months (range: 2 years 5 months-13 years 8 months) for 17 patients with 24 hips. Two patients died secondary to systemic illness. Seventeen hips (65.4%) had very good or good results using the Ficat criteria. Eight hips (30.8%) needed further operation [total hip arthroplasty (THA) for 7 hips, osteotomy for 1 hip]. Of the 12 hips in patients who had used steroids, 6 hips (50%) were converted to THA. Four hips in patients with systemic lupus erythematosus (SLE) needed THA (100%). We conclude that core decompression provides an effective treatment for steroid-associated osteonecrosis other than in cases with SLE, as well as providing effective treatment for non-steroid-associated osteonecrosis in the early stages of the disease.

Adult↗
PubMed2000

Gene therapy of transplant arteriopathy by liposome-mediated transfection of endothelial nitric oxide synthase.

BACKGROUND: Transplant arteriopathy is the major factor limiting long-term survival after cardiac transplantation. We have previously demonstrated that liposome-mediated gene delivery of endothelial nitric oxide synthase (eNOS) to donor hearts reduces ischemia-reperfusion injury by blocking NFkappaB activation, adhesion molecule expression, and leukocyte infiltration. In this study, we used gene transfer of eNOS in a rabbit carotid transplant model to see whether these same effects would similarly ameliorate transplant arteriopathy. METHODS: Liposomes complexed to the gene encoding eNOS were injected into donor carotid arterial segments that were transplanted orthotopically into recipient carotid arteries (n = 10). Controls included transplanted carotids transfected with liposomes complexed to empty plasmids (no functional gene) (n = 4) and transplanted carotids treated with saline (n = 6). Transplanted arteries were harvested for processing at 21 days. Intima/media (I/M) area ratios were calculated by computerized image analysis. Infiltrating T-lymphocytes and macrophages, and expression of VCAM-1 and ICAM-1 were quantified on immunocytochemistry. RESULTS: The I/M ratio was significantly reduced in eNOS-transfected arteries compared with arteries transfected with empty plasmids and saline-treated controls. Compared to transplanted control arteries, eNOS-transfected arteries demonstrated significantly reduced T-cell infiltration into the intima and significantly reduced macrophage infiltration into the media. Cell surface expression of VCAM-1 and ICAM-1 were both reduced in eNOS-transfected arteries. CONCLUSIONS: ENOS gene delivery can suppress neointimal lesion formation and T-lymphocyte and macrophage infiltration in transplanted arteries, associated with a reduction in relevant adhesion molecule expression. Thus, gene therapy with eNOS may not only reduce ischemia-reperfusion injury but may also ameliorate transplant arteriopathy in transplanted hearts.

Animals↗
PubMed2000

An experimental teleradiology transmission system using a high-speed ATM backbone network.

We evaluated the performance of an experimental teleradiology system based on a high-speed ATM backbone network. Image acquisition, transmission and the disk-to-display processing times were measured. Computerized tomography (CT) scans printed on 14 inch x 17 inch (36 cm x 43 cm) films were digitized and transferred over the network. The average time for the entire process was 1 min 30 s. Three radiologists interpreted 20 cases. For CT image interpretation, the reading time for one case ranged from 2 to 12 min (mean 6 min 46 s) on a monitor, and from 1 to 3 min (mean 1 min 31 s) with the original film. The ATM backbone network operating at 156 Mbit/s provided sufficient speed for remote consultation. However, further improvements in the operability of the system, especially the image viewing station, are necessary before it will be satisfactory for clinical use.

Computer Systems↗
PubMed2000

Chronic, traumatic intraconal hematic cyst of the orbit removed through the fronto-orbital approach--case report.

A 22-year-old male presented with a chronic encapsulated intraorbital hematoma 3 months after blunt trauma to his left eyeball. Ophthalmological examination found the best corrected visual acuity was 4/20 in the left eye, and 20/20 in the right eye. The orbit exhibited exophthalmus and inability of the eye to move above the horizontal level. Orbital magnetic resonance imaging showed a fairly well-demarcated area in the medial aspect of the orbit appearing as hyperintense on T1-weighted images and isoto hyperintense on T2-weighted images. This area was believed to be hemorrhage. No other abnormalities were found. The diagnosis was hematic cyst. The cyst was approached through a left fronto-orbital route and its location identified within the periorbita and orbital fat. The cyst was removed partially. Histological examination demonstrated cystic accumulation of blood and breakdown products in a non-epithelium-lined fibrous capsule, compatible with hematic cyst. The presence of hemosiderin in the cyst wall suggested that the cyst was a chronically enlarging lesion. Hematic cysts of the orbit usually present as subperiosteal mass months to years after trauma. Surgical removal of the cyst wall rather than needle aspiration is recommended to prevent recurrence.

Adult↗
PubMed2000

[Impending paradoxical embolism visualized by echocardiography combined with pulmonary embolism: a case report].

A 43-year-old man was admitted to our hospital complaining of dyspnea on exertion and dizziness. Transthoracic echocardiography revealed a mobile mass (3.5 x 1.0 cm) attached to the left atrial septum and transesophageal echocardiography showed the mass in the right atrium protruding through the patent foramen ovale into the left atrium. A mobile snake-like thrombus was apparent in the right atrium and right ventricle. The diagnosis was pulmonary embolism with impending paradoxical emboli.

Adult↗
PubMed1999

Acute and transient increase of lipocalin-type prostaglandin D synthase (beta-trace) level in cerebrospinal fluid of patients with aneurysmal subarachnoid hemorrhage.

We measured the concentration of lipocalin-type prostaglandin D synthase (PGDS) in cerebrospinal fluid (CSF) and serum in patients 1, 3, 5, 7, 9, 11, 14 and 17 days after subarachnoid hemorrhage (SAH) due to ruptured cerebral aneurysms. The PGDS level in lumbar CSF increased about two-fold at day 3 (20.85 +/- 2.71 microg/ml, mean +/- SE) and at day 5 (25.24 +/- 3.76), as compared with the level at day 1 (11.25 +/- 1.07). The CSF level gradually decreased and returned to the day 1 level at day 17. The serum PGDS level was much lower than the CSF level (0.39 +/- 0.06 at day 1) and almost unchanged until day 17. The neuron-specific enolase level in CSF, as an index of brain damage, was maximum at day 1 (29.83 +/- 7.32 ng/ml) and decreased at day 3 and at day 5 (18.28 +/- 2.65 and 11.95 +/- 1.82, respectively). These results suggest that the transient and delayed increase in the PGDS level in CSF is due to its induction of PGDS in the arachnoid membrane after SAH.

Aged↗
PubMed1999

Unilateral sciatic nerve injury stimulates contralateral nerve regeneration.

Axonal outgrowth in tissue cultures was measured to determine whether unilateral peripheral nerve injuries affect contralateral nerve regeneration. The right sciatic nerves of young male Wistar rats were cut at mid-thigh level. Sham operation as a control was limited to the exposure of the nerve without cutting. At day 6 post-surgery, bilateral L5 dorsal root ganglia (DRG) with attached nerve stumps were resected and cultured. Axonal outgrowth from the nerve stump was measured in situ. The contralateral preparations showed longer outgrowths than controls. Therefore the conditioning effect was not merely restricted to the ipsilateral neurons but also affected undamaged sensory neurons of the contralaretal DRG.

Animals↗
PubMed1999

Blood brain barrier destruction in hyperglycemic chorea in a patient with poorly controlled diabetes.

A case of hemichorea in a patient with poorly controlled diabetes is reported. T1-weighted magnetic resonance imaging (MRI) showed an unusual homogeneous high-intensity area in the corpus striatum. Of interest in the case was the fact that the globus pallidus, which was enhanced with gadolinium at the onset of hemichorea, showed homogeneous high-intensity on a subsequent T1-weighted image. This indicated that blood brain barrier destruction preceded the signal intensity change in the basal ganglia. As far as the authors could determine, this is the first reported case showing such enhancement during the course of diabetic hemichorea.

Anti-Dyskinesia Agents↗
PubMed1999

The time-dependent difference of GAP-43 expression between sensory neurons and motoneurons after peripheral nerve transection.

The L5 dorsal root ganglion (DRG) cells and L5 anterior horn (AH) cells of rats were studied and examined immunocytochemically after transection of the sciatic nerve to find out whether there would be time-dependent differences in the increase of growth-associated protein (GAP-43) expression between sensory neurons and motoneurons. On the seventh day after transection at mid-thigh level, the levels of GAP-43 in the DRG cells significantly increased, while those in the AH cells began to increase gradually from the 14th day onward. Transection at the piriform muscle level induced a significant increase in immunoreactivity of GAP-43 on the third day in the DRG cells, and on the seventh day in the AH cells. These results showed that sensory neurons expressed GAP-43 immunoreactivity earlier than motoneurons after peripheral nerve transection regardless of the site, suggesting that sensory neurons might start to produce cytoskeletons for axonal elongation earlier than motoneurons after nerve transection.

Analysis of Variance↗
PubMed1999

Growth phase-dependent variation in protein composition of the Escherichia coli nucleoid.

The genome DNA of Escherichia coli is associated with about 10 DNA-binding structural proteins, altogether forming the nucleoid. The nucleoid proteins play some functional roles, besides their structural roles, in the global regulation of such essential DNA functions as replication, recombination, and transcription. Using a quantitative Western blot method, we have performed for the first time a systematic determination of the intracellular concentrations of 12 species of the nucleoid protein in E. coli W3110, including CbpA (curved DNA-binding protein A), CbpB (curved DNA-binding protein B, also known as Rob [right origin binding protein]), DnaA (DNA-binding protein A), Dps (DNA-binding protein from starved cells), Fis (factor for inversion stimulation), Hfq (host factor for phage Q(beta)), H-NS (histone-like nucleoid structuring protein), HU (heat-unstable nucleoid protein), IciA (inhibitor of chromosome initiation A), IHF (integration host factor), Lrp (leucine-responsive regulatory protein), and StpA (suppressor of td mutant phenotype A). Intracellular protein levels reach a maximum at the growing phase for nine proteins, CbpB (Rob), DnaA, Fis, Hfq, H-NS, HU, IciA, Lrp, and StpA, which may play regulatory roles in DNA replication and/or transcription of the growth-related genes. In descending order, the level of accumulation, calculated in monomers, in growing E. coli cells is Fis, Hfq, HU, StpA, H-NS, IHF*, CbpB (Rob), Dps*, Lrp, DnaA, IciA, and CbpA* (stars represent the stationary-phase proteins). The order of abundance, in descending order, in the early stationary phase is Dps*, IHF*, HU, Hfq, H-NS, StpA, CbpB (Rob), DnaA, Lrp, IciA, CbpA, and Fis, while that in the late stationary phase is Dps*, IHF*, Hfq, HU, CbpA*, StpA, H-NS, CbpB (Rob), DnaA, Lrp, IciA, and Fis. Thus, the major protein components of the nucleoid change from Fis and HU in the growing phase to Dps in the stationary phase. The curved DNA-binding protein, CbpA, appears only in the late stationary phase. These changes in the composition of nucleoid-associated proteins in the stationary phase are accompanied by compaction of the genome DNA and silencing of the genome functions.

Bacterial Proteins↗
PubMed1999

Isolation from tobacco mosaic virus-infected tobacco of a solubilized template-specific RNA-dependent RNA polymerase containing a 126K/183K protein heterodimer.

The complete nucleotide sequence was determined for the putative RNA polymerase (183K protein) gene of tobacco mosaic virus (TMV) OM strain, which differed from the related strain, vulgare, by 51 positions in its nucleotide sequence and 6 residues in its amino acid sequence. Three segments of this 183K protein, each containing the sequence motif of methyltransferase (M), helicase (H), or RNA-dependent RNA polymerase (P), were expressed in Escherichia coli as fusion proteins with hexahistidine tags, and domain-specific antibodies were raised against purified His-tagged M and P polypeptides. By immunoaffinity purification, a template-specific RNA-dependent RNA polymerase containing a heterodimer of the full-length 183K and 126K (an amino-terminal-proximal portion of the 183K protein) viral proteins was isolated. We propose that the TMV RNA polymerase for minus-strand RNA synthesis is composed of one molecule each of the 183- and 126-kDa proteins, possibly together with two or more host proteins.

Base Sequence↗
PubMed1998

Molecular cloning and functional expression of feline thrombopoietin.

Feline thrombopoietin (TPO) was molecularly cloned to establish a basis for cytokine therapy of thrombocytopenia in cats. cDNA clones covering the whole coding sequence of feline TPO were isolated from feline liver. The feline TPO cDNA obtained in this study contained an open reading frame encoding 349 amino acid residues. The predicted amino acid sequence of feline TPO shared 78.7, 69.9, 72.9 and 83.0% similarity with sequences of human, murine, rat and canine TPO, respectively. Four cysteine residues and two of four N-glycosylation sites that are conserved among species were also found at the corresponding positions in feline TPO. The feline TPO cDNA fragment encoding the whole amino acid coding region was recloned into an expression vector, and the resulting vector was transfected into 293T cells using the calcium phosphate method. The supernatant of the transfected 293T cells stimulated the proliferation of a human megakaryoblastic leukemia cell line (UT-7/TPO) cells in a dose dependent manner, indicating that the feline TPO cDNA obtained in this study encodes biologically active feline TPO.

Amino Acid Sequence↗
PubMed1998

Electro-optic Properties of Colloidal Crystals As Studied by Reflection Spectroscopy.

Electro-optic properties of colloidal crystals of silica spheres in the exhaustively deionized aqueous suspension have been studied by the reflection spectroscopy using a T-type cell. Acoustic shear waves are induced when sine-wave electric fields ranging from 0.01 to 1 Hz are applied. Modulation effects of the crystals on the applied AC fields such as phase delay, change in response intensity, waveform transformation, and harmonics generation are observed. The shear waves propagate outside the electrodes where the electric field is absent. The synchronous fluctuation of the colloidal spheres including expanded electrical double layers in the crystal lattice will be one of the main causes of the electro-optic nature of the crystals. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Differential induction of immediate early gene mRNAs following cryogenic and impact trauma with/without craniotomy in rats.

Expression of immediate early gene (IEG) mRNAs following traumatic brain injury in 3 different models-cryogenic injury, impact injury with craniotomy and impact injury without craniotomy-was investigated using in situ hybridization. Cryogenic brain injury resulted in c-fos and c-jun mRNA expression throughout the ipsilateral cortex, piriform cortex and dentate gyrus on the injured side, with peak at 30 min to 1 h post-injury. Impact injury with craniotomy was associated with hybridization signals in the same areas and also in the subcortical white matter or ependyma underlying the impact site at 30 min post-injury. The expression was rather more prolonged than with cryogenic injury. Impact injury without craniotomy induced the expression of both mRNAs throughout the ipsilateral cortex, piriform cortex and dentate gyrus at 30 min post-injury, but this was promptly attenuated by 1 h post-injury, except for bilateral elevation in the dentate gyrus. The present study, thus, demonstrated that regional and temporal expression of IEG mRNAs is influenced by the intensity, quality and manner of application of the insult. Differences in the expression of IEGs may alter the late response gene expression and affect the succeeding events.

Animals↗
PubMed1998

Two large subunits of the fission yeast RNA polymerase II provide platforms for the assembly of small subunits.

The subunit-subunit contact network was analyzed for the Schizosaccharomyces pombe RNA polymerase II consisting of ten putative subunits. Previously we carried out far-Western blot analysis of bimolecular interaction with radio-labeled subunit 3 and 5 probes. Here we extended the analysis using another six small-sized subunits as probes. Taking the results together the subunit-subunit interaction was observed for a total 18 (or 19) combinations. All eight small-sized subunits exhibited binding activities to two large subunits, Rpb1 and Rpb2. In addition, bimolecular interaction was observed for the combinations of Rpb3-Rpb5, Rpb3-Rpb11 (and Rpb5-Rpb8/11). The subunit-subunit contact within the assembled RNA polymerase was then analyzed by protein-protein cross-linking using five species of bifunctional cross-linkers with different length and specificity. Cross-linking was observed for a total of 19 combinations, including five combinations between small subunits, Rpb3-Rpb10, Rpb3-Rpb11, Rpb5-Rpb6, Rpb6-Rpb7 and Rpb6-Rpb8. The results altogether indicate that two large subunits Rpb1 and Rpb2 provide the platform for assembly of small subunits and also small subunits interact with each other for limited combinations. Direct contact of the two large subunits, Rpb1 and Rpb2, was also demonstrated by cross-linking.

Cross-Linking Reagents↗