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Biomedical subjects

H Akashi

Publications and source records attributed to H Akashi.

At least 73 records · Page 4Linked to original sources
PubMed1998

Evaluation of equine infectious anemia virus core proteins produced in a baculovirus expression system in agar gel immunodiffusion test and enzyme-linked immunosorbent assay.

Equine infectious anemia virus (EIAV) core proteins (Gag and p26) obtained from a baculovirus expression system were used in agar gel immunodiffusion (AGID) and enzyme-linked immunosorbent assay (ELISA) antigens to test seventy-six horse sera. Those sera showed false-positive reaction in AGID test using Nisseiken antigen. However, none of them showed false-positive reaction with both of the expressed antigens. The 76 horse sera were also tested by ELISA. The sera gave a high background in ELISA using Nisseiken antigen. Gag and p26 reacted strongly against positive sera from horses immunized with Nisseiken antigen.

Animals↗
PubMed1998

Effect of heparin on hemagglutination by equine arteritis virus.

Heparin inhibited hemagglutination (HA) by equine arteritis virus (EAV) as well as did HA by Aujeszky's disease virus (ADV), but failed to inhibit HA by parainfluenza virus type 3 (PIV-3). The minimal concentration of heparin required to inhibit 8 HA U of EAV was 0.1 U/ml. In addition, most EAV hemagglutinin was retained by heparin acrylic beads, as was ADV hemagglutinin, but was not PIV-3 hemagglutinin. Mouse erythrocytes failed to combine with the HA inhibitory factor of heparin. However, mouse erythrocytes treated with heparinase had greatly reduced agglutinability by EAV. All these findings suggest that a heparin-like molecule on the surface of mouse erythrocytes serves as the virus-cell receptor.

Animals↗
PubMed1998

MRI monitoring of tarsal navicular stress fracture healing--a case report.

Stress fractures of the tarsal navicular bone are rare injury and assessing its healing is difficult. Tenderness over the tarsal navicular on physical examination is the most reliable sign for assessing fracture healing. However, it is desirable to assess fracture healing with some imaging method. We used serial magnetic resonance imaging (MRI) to assess healing in a patient with a tarsal navicular stress fracture. MRI was useful for the assessment of fracture healing of tarsal navicular stress fracture in our case.

Adolescent↗
PubMed1998

A new reduction technique for a patellar fracture.

We report 4 cases of patellar fracture with skin injury over the patella which were treated operatively immediately after onset with a new reduction technique using Ilizarov pins. This technique made it possible to perform early operative treatment even in the cases with skin injury over the patella which prevents conventional surgical approach.

Adult↗
PubMed1998

Safety management of a patient undergoing thoracic aortic surgery by spinal evoked potential monitoring.

We have presented a patient (48 year-old male) in whom the evoked spinal potential monitor detected impending spinal ischemia after aortic cross-clamping, which allowed surgical intervention to be modified so as to restore the decaying evoked spinal potential. The patient received replacement of the dissecting aneurysm in the thoracic descending aorta with clamping of the aorta at the sites immediately proximal and distal to the aneurysm and initiation of femoro-femoral venoarterial bypass under normothermia. The evoked spinal potential was recorded via the T12/L1 epidural electrode in response to transdural electric stimulation of the spinal cord at the C7/T1 level. As the evoked spinal potential gradually decreased in amplitude without latency prolongation after aortic cross-clamping, the distal clamp was moved from the T6 vertebral level to the T4. The reduced spinal potential then returned to the baseline amplitude. This episode was repeated twice from surgical necessity. The patient was free from any neurological disorders postoperatively.

Aortic Dissection↗
PubMed1998

Immunohistochemical detection of MUC2 mucin core protein in ulcerative colitis.

MUC2 mucin is predominantly expressed in the colon and is considered to play an important role in the protection of that organ. Recent findings suggested that MUC2 protein levels are significantly decreased in active ulcerative colitis (UC). We therefore performed an immunohistochemical study to reveal if the expression of MUC2 protein is altered in UC. Seventy-nine biopsy tissue specimens from 31 UC patients, along with normal colon tissues, were immunostained with anti-MUC2 mucin core protein monoclonal antibody (MoAb) CCP58 (IgG1). UC tissue specimens were divided into two groups based on the histological severity of inflammation, i.e., 64 with active inflammation (grades 2-5) and 15 without (grade 1). In the former group, 52 out of 64 (81.3%) tissue specimens contained sections of glands with a few cells positive for MoAb CCP58. These glands were small and consisted of MUC2 negative-short cells and a few positive cells without apparent mucus formation, considered to be immature regenerative glands. In contrast, the staining pattern was almost the same as that of the normal colon and no immature glands were seen in the group without active inflammation. The sections of immature regenerative glands with a few MUC2-positive cells were exclusively found in the UC tissues with active inflammation, but not in those without it, suggesting that the expression of MUC2 protein may be decreased in active UC.

Adolescent↗
PubMed1998

Mutation pressure, natural selection, and the evolution of base composition in Drosophila.

Genome sequencing in a number of taxa has revealed variation in nucleotide composition both among regions of the genome and among functional classes of sites in DNA. Mutational biases, biased gene conversion, and natural selection have been proposed as causes of this variation. Here, we review patterns of base composition in Drosophila DNA. Nucleotide composition in Drosophila melanogaster varys regionally, and base composition is correlated between introns and exons. Drosophila species also show striking patterns of non-random codon usage. Patterns of synonymous codon usage and the biochemistry of translation suggest that natural selection may act at 'silent' sites. A relationship between recombination rates and codon usage and comparisons of the evolutionary dynamics of silent mutations within and between species support natural selection discriminating among synonymous codons. The causes of regional base composition variation are less clear. Progress in functional studies of non-coding DNA, further investigations of genome patterns, and statistical tests based on evolutionary theory will lead to a greater understanding of the contributions of mutational processes and natural selection in patterning genome-wide nucleotide composition.

Animals↗
PubMed1998

[Surgical treatment of an aortic arch aneurysm: reports of 2 cases with lesion of the arch vessels].

A 48-year old woman underwent surgery for an aortic arch aneurysm with stenosis or dilatation of three arch vessels caused by aortitis syndrome. Total arch replacement and reconstruction of three arch vessels were performed with hypothermic selective cerebral perfusion (SCP). To avoid atheroembolism and malperfusion to the brain, the rt. common carotid artery was perfused via the rt. subclavian artery through the dacron vascular graft and the lt. subclavian artery was cannulated and perfused distally to stenosis. A 65-year-old man who had an atherosclerotic aortic arch aneurysm with severe stenosis of the brachiocephalic artery underwent operation. In the operation, extracorporeal circulation was instituted with the arterial return through the lt. subclavian artery. Same as case 1, total arch replacement and reconstruction of three arch vessels were performed under hypthermic SCP. In this case, the left common carotid artery was transected and cannulated directly into the vessel, instead of cannulation through the aortic lumen because of atheromatous plaques in the orifice of the left common carotid artery. The patients recovered uneventfully and doing well now.

Aged↗
PubMed1997

Codon bias evolution in Drosophila. Population genetics of mutation-selection drift.

Although non-random patterns of synonymous codon usage are a prominent feature in the genomes of many organisms, the relatives roles of mutational biases and natural selection in maintaining codon bias remain a contentious issue. In some species, patterns of codon bias and empirical findings on the biology of translation suggest 'major codon preference', a balance among mutation pressure, genetic drift, and weak selection in favor of translationally superior codons. Population genetics theory makes testable predictions to distinguish such a model from a strictly mutational model of codon bias. Major codon preference predicts two fitness classes of synonymous DNA changes: 'preferred' mutations from non-major to major codons and 'unpreferred' changes in the opposite direction. An extension of current statistical methods is employed to reveal differences in the within and between species dynamics of preferred and unpreferred silent mutations in Drosophila simulans. In this lineage, codon bias appears to be maintained under roughly equal magnitudes of natural selection and genetic drift. In the sibling species, D. melanogaster, however, a reduction in N(e)s, the product of effective population size and selection coefficient, appears to have allowed a genome-wide reduction in codon bias.

Animals↗
PubMed1997

A novel gastric-cancer-associated mucin antigen defined by a monoclonal antibody A3D4.

De-glycosylation of mucins may expose new tumor-associated core protein epitopes. In this study, to attempt to develop useful markers for gastric cancers, we have purified and de-glycosylated gastric mucin and tried to establish monoclonal antibodies (MAbs). A MAb designated A3D4 among established MAbs was shown to react with gastric cancer with high frequency, but not with normal gastric epithelium. Among normal digestive organs, only the colon and gall bladder were positive for MAb A3D4. The incidence of positivity in gastric cancer was 75% for intestinal-type adenocarcinoma (n = 28), 40% for solid-type adenocarcinoma (n = 5) and 33% for signet/scirrhous-type adenocarcinoma (n = 15). Interestingly, adenoma and intestinal metaplasia (IM) with chronic gastritis or peptic ulcer were negative for MAb A3D4, whereas 8 out of 13 cases (62%) of IM with gastric cancer was positive. Western-blot analysis using the lysate from normal colon tissues revealed a high-molecular-weight (> 300-kDa) smear-like band. Immunohistochemical analysis indicated that the reactivity of MAb A3D4 was clearly increased when tissue sections were pre-treated with periodic acid or O-glycanase, while it was decreased by pre-treatment with trypsin or protease V8. There was no reactivity with the synthetic peptide encompassing the tandem-repeat sequence of MUC2 or MUC3. These data suggest that MAb A3D4 detects a novel gastric-cancer-associated mucin antigen whose epitope may be peptide in nature.

Adenocarcinoma↗
PubMed1997

Operation for type B aortic dissection using hypothermic selective cerebral perfusion.

A 56-year-old man who had a huge type B dissecting aortic aneurysm extending from the distal arch to the thoracoabdominal aorta underwent replacement of the descending thoracic and thoracoabdominal aorta under hypothermic circulatory arrest with selective cerebral perfusion. The intercostal arteries at the T-8 to T-11 level were preserved with beveled distal anastomosis, and the celiac artery and the intercostal arteries at the T-5 and T-6 levels were reconstructed. The patient recovered uneventfully and is presently doing well 1 year after the operation.

Aortic Dissection↗
PubMed1997

Antigenic diversity of Akabane virus detected by monoclonal antibodies.

The antigenic properties of 21 Japanese field isolates and two Australian strains of Akabane (AKA) virus (Simbu serogroup, bunyavirus) isolated from 1959 to 1990 were compared by enzyme-linked immunosorbent assay (ELISA), plaque-reduction neutralization (PRNT) and hemagglutination inhibition (HI) tests using monoclonal antibodies (Mabs) to the OBE-1 strain of AKA virus. Sixteen Mabs were established by fusing P3X63Ag8U1 mouse myeloma cells and spleen cells from BALB/c mice immunized with the OBE-1 strain. Of the 16 clones, 13 produced immunoglobulin (Ig) which precipitated glycoprotein G1 and three produced Ig which precipitated nucleoprotein (N). Twelve out of 13 Mabs had both NT and HI activities to not only the homologous OBE-1 strain but also the other isolates. By the competitive binding assay, at least five antigenic regions for G1, and two for N were defined. Some of the anti-G1 Mabs which reacted to the same antigenic region had unique reactivity while anti-N Mabs recognizing the same epitope reacted with almost the same degree to all of the isolates. Finally, nine epitopes of the G1 protein in five different antigenic regions have been identified. There was no striking correlation between isolation date and place of the isolates and their reactivity to Mabs. A most interesting result is that three isolates collected in the same place over a three week period had different reactivity patterns detected by ELISA, showing great antigenic variation of the virus. AKA virus may be a single gene pool consisting of different genotypes in the field.

Animals↗
PubMed1997

Antigenic and genetic comparisons of Japanese and Australian Simbu serogroup viruses: evidence for the recovery of natural virus reassortants.

The antigenicity and RNA genome structures of five Simbu serogroup bunyaviruses isolated in Japan and Australia were analyzed using monoclonal antibodies (Mabs) raised to Akabane (AKA) virus and oligonucleotide fingerprinting. The virion surface glycoprotein (G1) and the nucleocapsid (N) protein of heterologous viruses showed no reactivity to the Mabs, while the AKA-derived anti-G1 Mab (2F1) reacted with Peaton virus and all three AKA anti-N Mabs reacted with Tinaroo (TIN) virus at almost the same antibody titers as the homologous virus. Oligonucleotide fingerprinting analyses indicated that the three RNA species of all the viruses were unique and distinguishable. However, AKA and TIN viruses exhibited very similar S RNA oligonucleotide fingerprints, while the L and M RNA fingerprints were quite different. The S RNA sequence of TIN virus has been determined and compared with that of AKA and Aino viruses. The results revealed 95.1% S sequence homology between the AKA and TIN viruses. The antigenic and genetic comparisons of AKA and TIN viruses suggest that the two viruses may represent naturally occurring reassortant viruses.

Amino Acid Sequence↗
PubMed1997

Aneurysm of aberrant right subclavian [corrected] artery arising from diverticulum of Kommerell. Report of a case with tracheal compression.

A 74-year-old woman presented with severe dyspnea without dysphagia. Computed tomographic scans and Digital subtraction angiography revealed the left aortic arch with an aberrant right subclavian artery arising from the Kommerell's diverticulum and tracheal compression. The aortic arch and the Kommerell's diverticulum were aneurysmal and were responsible for this compression. Surgical relief was accomplished by replacement of the aortic arch and reconstruction of the four brachiocephalic vessels with vascular prostheses through a median sternotomy incision extending into the right supraclavicular region.

Aged↗
PubMed1997

Natural selection and the frequency distributions of "silent" DNA polymorphism in Drosophila.

In Escherichia coli, Saccharomyces cerevisiae, and Drosophila melanogaster, codon bias may be maintained by a balance among mutation pressure, genetic drift, and natural selection favoring translationally superior codons. Under such an evolutionary model, silent mutations fall into two fitness categories: preferred mutations that increase codon bias and unpreferred changes in the opposite direction. This prediction can be tested by comparing the frequency spectra of synonymous changes segregating within populations; natural selection will elevate the frequencies of advantageous mutations relative to that of deleterious changes. The frequency distributions of preferred and unpreferred mutations differ in the predicted direction among 99 alleles of two D. pseudoobscura genes and five alleles of eight D. simulans genes. This result confirms the existence of fitness classes of silent mutations. Maximum likelihood estimates suggest that selection intensity at silent sites is, on average, very weak in both D. pseudoobscura and D. simulans (magnitude of NS approximately 1). Inference of evolutionary processes from within-species sequence variation is often hindered by the assumption of a stationary frequency distribution. This assumption can be avoided when identifying the action of selection and tested when estimating selection intensity.

Animals↗