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Biomedical subjects

H Imagawa

Publications and source records attributed to H Imagawa.

At least 19 recordsLinked to original sources

Genomic RNA constellation of recently emerging serotype G14 equine rotavirus strains in Japan that is highly homologous with prototype G3 and G14 strains previously identified in the United States of America.

Serotype G14 was once considered to be uncommon among equine rotaviruses. While it sporadically emerged in some parts of the world, serotype G14 became the dominant G serotype among rotaviruses detected in foals with diarrhea in Japan in the late 1990s. However, it is not known how such recently emerging G14 rotaviruses are related in their overall genomic RNA constellation to prototype G14 strain identified earlier in the United States of America or how they were generated and why they have dominated over G3 equine rotaviruses. Genogrouping by RNA-RNA hybridization revealed that recently emerging serotype G14 equine rotavirus strains had an overall genomic RNA constellation that was highly conserved not only with contemporary and earlier G3 strains in Japan but also with prototype G3 and G14 strains previously identified in the United States of America. Japanese G14 rotavirus strains are likely to have originated form a VP7 gene substitution reassortant that had been formed earlier in the United States of America on the background of the then dominant G3 equine rotavirus.

Animals↗

[Assessment of extracellular fluid in cardiac surgery using cardiopulmonary bypass].

Extracellular fluid (ECF) was assessed before and after the cardiac surgery using cardiopulmonary bypass (CPB), by means of a bioimpedance spectrum analyzer to see volumes of the fluid based on changes of the impedance to various frequencies. Difference between the levels before and after the operation was divided by body weight to study about a % BW. Simultaneously its relation to the lung compliance [tidal volume/(peak inspiratory pressure-end expiratory pressure)] was studied. Mean age of the 18 patients was 59.1 +/- 19 years old. ECF was assessed before to 24 hours after the operation continuously and once more after 48 hours. Mean CPB time was 165 +/- 52 minutes, and aortic cross clamp time was 121 +/- 4 minutes. A remarkable increase of ECF was noted immediately after the operation, which further increased gradually till arriving at the peak 4 hours after the operation (4.52 +/- 1.8% BW). Then it gradually decreased to 0.641 +/- 2.7% BW 48 hours later. Lung compliance measured at the same time showed the lowest level 6 hours after the operation. It was known that the bioimpedance spectrum analysis is a simple and non-invasive method, which enables to monitor the vital stable before and after the operation.

Adult↗

Detection of antibodies to the nonstructural protein (NS1) of influenza A virus allows distinction between vaccinated and infected horses.

Antibodies to the nonstructural protein (NS1) of A/equine/Miami/1/63 (H3N8) influenza virus were detected exclusively in the sera of mice experimentally infected with A/Aichi/2/68 (H3N2) and horses infected with A/equine/Kentucky/1/81 (H3N8) or A/equine/La Plata/1/93 (H3N8), but not in those of the animals immunized with the inactivated viruses, by enzyme-linked immunosorbent assay (ELISA) using a recombinant NS1 as antigen. The results indicate that the present method is useful for serological diagnosis to distinguish horses infected with equine H3 influenza viruses from those immunized with the inactivated vaccine.

Animals↗

Predominance of G3B and G14 equine group A rotaviruses of a single VP4 serotype in Japan.

A total of 65 equine group A rotaviruses (GAR) isolated from diarrheal foals at 48 farms in Hokkaido, Japan, between 1996 (29 isolates) and 1997 (36 isolates) were characterized for their VP7 and VP4 serotypes by PCR, nucleotide sequencing, and virus neutralization (VN) tests. By PCR VP7 typing, all isolates were classified as G3 or G 14, and the predominant serotype in each year was G3 (86%) in 1996 and G14 (53%) in 1997. VN tests with these 20 isolates randomly selected confirmed the specificity of PCR on the bases of complete agreement of the results in these methods (9 G3 and 11 G14), and revealed that all 9 G3 isolates were subtype G3B. There were five differing amino acid residues in three VP7 antigenic regions between subtypes G3A and G3B. Antiserum to a baculovirus recombinant that expressed P[12] VP4 neutralized all isolates and P[12] reference strains. These results suggest that genotype P[12] GAR belong to a single VP4 serotype, and that one VP4 and two VP7 serotypes (G3B and G14) of GAR were predominant in the equine population in Japan.

Amino Acid Sequence↗

Serological diagnosis of equine influenza using the hemagglutinin protein produced in a baculovirus expression system.

The hemagglutinin (HA) protein of an equine influenza strain, A/equine/La Plata/1/93 (LP/93), was produced using a baculovirus expression system. Silkworm larvae inoculated with recombinant baculovirus expressed high quantities of the HA protein which was then purified to greater than 95% purity by fetuin-affinity chromatography. Purified HA protein was used subsequently in an ELISA for detection of antibodies in horse sera. Two hundred serum samples from vaccinated racehorses were reacted on ELISA plates coated with 40.0 ng/ml of purified HA protein. Subsequent optical density (OD) levels revealed titers which correlated highly with respective hemagglutinin inhibition (HI) antibody titers which ranged from <1:8 to 1:256 (correlation coefficient among them was 0.850). ELISA OD levels and HI titers increased at 5 and 7 days post-inoculation, respectively, in a horse inoculated intranasally with LP/93. Respective antibody levels were observed to change in an essentially parallel manner during a period of 1 month. Similarly, ELISA OD levels correlated with HI titers in horses during a period of 6 weeks following intramuscular inoculation with inactivated single-strain vaccines containing LP/93, A/equine/Kentucky/1/81 (H3N8) or A/equine/Rome/5/91 (H3N8). A similar pattern was also observed in eight horses throughout a 10-week period following inoculation with a commercially available inactivated trivalent vaccine containing A/equine/Newmarket/1/77(H7N7), A/equine/Kentucky/81 and LP/93. From these results, it is suggested that this ELISA system could be used for disease diagnosis and surveillance of HI antibody titers among vaccinated horses.

Animals↗

Antigenic variation among equine H 3 N 8 influenza virus hemagglutinins.

To provide information on the antigenic variation of the hemagglutinins (HA) among equine H 3 influenza viruses, 26 strains isolated from horses in different areas in the world during the 1963-1996 period were analyzed using a panel of monoclonal antibodies recognizing at least 7 distinct epitopes on the H 3 HA molecule of the prototype strain A/equine/Miami/1/63 (H 3 N 8). The reactivity patterns of the virus strains with the panel indicate that antigenic drift of the HA has occurred with the year of isolation, but less extensively than that of human H 3 N 2 influenza virus isolates, and different antigenic variants co-circulate. To assess immunogenicity of the viruses, antisera from mice vaccinated with each of the 7 representative inactivated viruses were examined by neutralization and hemagglutination-inhibition tests. These results emphasize the importance of monitoring the antigenic drift in equine influenza virus strains and to introduce current isolates into vaccine. On the basis of the present results, equine influenza vaccine strain A/equine/Tokyo/2/71 (H 3 N 8) was replaced with A/equine/La Plata/1/93 (H 3 N 8) in 1996 in Japan. The present results of the antigenic analysis of the 26 strains supported the results of a phylogenetic analysis, that viruses belonging to each of the Eurasian and American equine influenza lineages have independently evolved. However, the current vaccine in Japan consists of two American H 3 N 8 strains; A/equine/Kentucky/1/81 and A/equine/La Plata/1/93. It is also therefore recommended that a representative Eurasian strain should be included as a replacement of A/equine/Kentucky/1/81.

Animals↗

The C-ring problem of sterol biosynthesis: TiCl(4)-induced rearrangement into the anti-Markovnikov cation corresponding to the C-ring.

[reaction: see text] Cation 9, generated by the reaction of diol 8 and BF(3).Et(2)O, SnCl(4), Sc(OTf)(3), FeCl(3), TiF(4), or CF(3)SO(3)H, leads to a hydride shift, providing cation 11, which corresponds to the initiation of backbone rearrangement. On the other hand, TiCl(4) selectively induces rearrangement to secondary cation 13 by ring expansion, which corresponds to the C-ring formation of sterol biosynthesis. AlCl(3) and ZrCl(4) induce further rearrangement into six-membered ring tert-cation 16.

Cations↗

Purification of horse immunoglobulin isotypes based on differential elution properties of isotypes from protein A and protein G columns.

Elution properties of horse immunoglobulin isotypes from protein A and protein G columns were examined. IgGa and IgGb isotypes were bound to protein A and protein G columns and were eluted by adjusting the pH of the elution buffer from 8.0 to 2.0. IgGc bound to protein G column but not to protein A column while IgG(T) bound to both columns. IgM and IgA apparently appeared not to bind to either column. New methods for purification of serum isotypes were developed using protein A and protein G columns as well as formerly established methods. Using these methods, it was possible to obtain purified isotypes for establishment of immunological assays for practical clinical use.

Animals↗

Pericardial hood repair of cardiac rupture secondary to extended myocardial infarction.

A surgical technique for simple and safe repair of oozing-type postinfarction cardiac rupture secondary to extended myocardial infarction is described. A hood-shaped pericardium was glued with gelatin-resorcinol and formaldehyde glue to cover the extended oozing infarcted myocardium. This technique was used on 3 elderly patients with good results.

Aged↗

In vitro detection of equine arteritis virus from seminal plasma for identification of carrier stallions.

Equine arteritis virus (EAV) was readily isolated in RK-13 cell monolayers by plaque assay from seminal plasma of experimental carrier stallions when they contained high titers of virus regardless of the presence of non-viral cytotoxicity in the seminal plasma. The cytotoxicity interfered with virus isolation from seminal plasma which contained virus at titers less than 10 PFU/ml. However, it was possible to detect the virus in seminal plasma pretreated with PEG (#6000). EAV was consistently identified by RT-PCR from crude seminal plasma which contained virus at titers of more than 10(2.7) PFU/ml. In vitro detection of EAV by virus isolation supplemented with RT-PCR using seminal plasma was proved to be an effective alternative to the standard test mating as a diagnostic method for carrier stallions.

Animals↗

Inhibitory effect of trehalose dimycolate (TDM) and its stereoisometric derivatives, trehalose dicorynomycolates (TDCMs), with low toxicity on lung metastasis of tumour cells in mice.

We examined the effect of semisynthetic trehalose-6,6 '-dimycolate (TDM) and its synthetic stereoisomeric derivatives (trehalose 6,6'-dicorynomycolates; TDCMs) prepared in oil-in-water (o/w) emulsion on inhibition of lung metastasis produced by highly metastatic murine tumour cells, colon 26-M3.1 carcinoma and B16-BL6 melanoma cells, using experimental and spontaneous metastasis models. Intravenous (i.v.) administration of TDM (100 microg/mouse) 1, 3 or 8 days before tumour inoculation significantly inhibited lung metastasis of colon 26-M3.1 cells, in a dose-dependent manner. Single administration of TDM 1 day after tumour inoculation also showed the therapeutic effect on experimental lung metastasis of colon 26-M3.1 cells. Similarly, multiple administrations of TDM after tumour inoculation resulted in a significant inhibition of spontaneous lung metastasis of B16-BL6 cells (on day 35), although it showed no effect on suppression of tumour growth (on day 21). In comparison of toxicity in vivo among TDM and four TDCMs such as TDCM(2R,3R), TDCM(2S,3R), TDCM(2R,3S) and TDCM(2S,3S), all of the TDCMs appeared to be less toxic than TDM itself. Furthermore, all of the TDCMs were prophylactically as well as therapeutically active for inhibition of lung metastasis of both colon 26-M3.1 and B16-BL6 tumour cells, showing higher inhibitory activity than that of TDM. In particular, TDCMs induced a marked suppression of the growth of B16-BL6 tumour cells in vivo. These results suggest that systemic administration of TDM as well as TDCMs led to inhibition of tumour metastasis and TDCMs are more potential to suppress tumour growth and inhibit tumour metastasis than TDM.

Adjuvants, Immunologic↗

Analysis of the elephant trunk method in patients with extensive thoracic aortic aneurysm.

We assessed the appropriate length of an elephant trunk prosthesis based on our experience with 9 patients experiencing extensive thoracic aneurysms. There were 3 patients with a true aneurysm, 5 patients with a dissecting aortic aneurysm, and 1 patient with a true plus dissecting aortic aneurysm. The subjects were 4 men and 5 women and, at the time of operation, were from 38 to 74 years old. The second-stage operations were performed on 6 patients from 9 days to 6 months after the first-stage operation. In the first-stage operation, one patient died of pneumonia during the hospital stay and another died of multi-organ infarction after 15 months. In the second-stage operation, two patients died of brain hemorrhage in the chronic stage after the operation. The length of the elephant trunk prosthesis was 3 cm in the three early patients, and in one of them the elephant trunk could not be utilized due to its insufficient length. In the next three patients, the length was extended to 5 cm, but one of patient experienced an expansion of the aneurysm in the descending aorta due to a graft of insufficient length which could not decompress the aneurysmal wall. Therefore, in the last three patients, the length was further extended to 10 cm, and the second-stage operation was performed uneventfully on the 64th, 9th and 45th day, respectively after the first-stage operation within a continuous hospital stay. Neither expansion of the aneurysm nor thromboembolism was found during the waiting period for any of the second-stage operations. Accordingly, we recommend using a 10 cm elephant trunk prosthesis.

Adult↗

Production of monoclonal antibodies to six isotypes of horse immunoglobulin.

Stable clones of 18 mouse hybridomas that produce monoclonal antibodies (MAbs) to six isotypes of horse immunoglobulin were produced. The number of hybridomas of different specificities are: four to IgGa, four to IgGb, one to IgGc, four to IgG(T), two to IgM, and three to IgA. The immunoglobulin isotypes purified from affinity columns bound with each MAb showed variable mobility in agarose-gel electrophoresis. Migration proceeded from the anode as: IgG(T), IgA, IgM, IgGc, IgGb and IgGa. The purified isotypes also demonstrated a single precipitin line when in immunoelectrophoresis against isotype-specific or polyclonal antisera, raised against the purified isotype or whole equine serum, respectively.

Animals↗

An equine herpesvirus type 1 recombinant with a deletion in the gE and gI genes is avirulent in young horses.

The cell culture-adapted KyA strain of equine herpesvirus type 1 (EHV-1) has been found to be attenuated in young horses (Matsumura et al., 1996, Vet. Microbiol. 48, 353-365). The KyA strain lacks at least six genes in its genome, including those encoding glycoproteins gE and gI. To elucidate whether EHV-1 glycoproteins gE and gI play a role in viral virulence, we have constructed an EHV-1 recombinant that has the genes encoding both gE and gI deleted from its genome and its revertant. Growth properties of the deletion mutant virus in vitro were compared with those of the parent and the revertant viruses. Plaque size of the mutant virus in fetal horse kidney (FHK) cells was significantly smaller than those of the parent and the revertant viruses. In one-step growth experiments, however, the yields of infectious virus from FHK cells infected with the deletion mutant, the parent, or the revertant virus were approximately the same. The results suggested that gE and/or gI of EHV-1 promoted cell-to-cell spread of the virus, but that these glycoproteins were not involved in the process of virus maturation and release or in virus attachment and penetration. Subsequently, the virulence of mutant and revertant viruses was examined in young horses. No clinical signs were observed in six horses, including three colostrum-deprived foals inoculated intranasally with the deletion mutant virus, whereas three colostrum-deprived foals inoculated intranasally with the revertant virus manifested clinical signs typical for EHV-1 respiratory infection (i.e., pyrexia, nasal discharge, and swelling of submandibular lymph nodes). The results obtained from in vivo studies revealed that the EHV-1 mutant defective in both gE and gI genes was avirulent in young horses, suggesting that gE and/or gI of the EHV-1 have an important role in EHV-1 virulence. However, the EHV-1 mutant defective in both gE and gI genes induced only a partial protectivity in inoculated foals from manifestation of respiratory symptoms after challenge infection.

Animals↗

[Painless aortic dissection late after aortic valve replacement, presenting as superior vena cava syndrome].

A 68-year-old man, who had underwent aortic valve replacement (AVR) with Björk-Shiley disc valve for aortic regurgitation 17 years ago, was transferred to our hospital complaining of facial redness and swelling, without chest or back pain. Preoperative examination revealed DeBakey type II aortic dissection, which caused superior vena cava syndrome (SVC syndrome). Emergent ascending aortic replacement was performed, postoperatively central venous pressure (CVP) decreased from 33 to 9 mmHg, and SVC syndrome was relieved. Painless aortic dissection after AVR, presenting as SVC syndrome, is a rare case, and close follow-up should be performed under consideration of painless aortic dissection late after AVR.

Aged↗

Postinfarction left-ventricular aneurysm: regional stress, function, and remodeling after aneurysmectomy.

BACKGROUND: Left-ventricular (LV) aneurysm formation after myocardial infarction (MI) leads to LV remodeling with global and regional cardiac dysfunction. LV aneurysmectomy (LVA) can often improve LV function, but changes of regional wall stress and systolic function in the noninfarcted segment before and after the operation remain poorly understood. The purpose of this study was to assess the effects of LVA on regional stress and systolic function in the noninfarcted region and to examine this procedure's impact on the LV remodeling in patients with LV aneurysm after myocardial infarction (MI). METHODS: Using quantitative left ventriculography and pressure measurements, 11 patients with an anterior LV aneurysm were studied before and 8 months after standard linear repair (LVA group), and 10 patients with an anterior transmural infarction who received coronary artery bypass grafting were also studied (CABG group) in an attempt to separate the effects of aneurysmectomy from the effects of bypass surgery. Regional end-systolic (ESS) and end-diastolic (EDS) stresses of the contractile segment (CS) were computed by Janz's method. RESULTS: The total ejection fraction (EF) increased (p < 0.01) in the LVA group, whereas it did not change in the CABG group at 8 months after surgery. Both the end-diastolic and end-systolic volume indices of CS decreased (p < 0.01 and p < 0.01, respectively) in the LVA group, whereas both remained unchanged in the CABG group. The mean velocity of circumferential fiber shortening (mean Vcf) of CS increased substantially (p < 0.01) in the LVA group and, less significantly (p < 0.05), in the CABG group. Regional ESS and EDS decreased (p < 0.01 and p < 0.05, respectively) in the LVA group, whereas both remained unchanged in the CABG group. The increase in mean Vcf correlated strongly with the magnitude of decrease in ESS (r = -0.63, p < 0.01) in the LVA group but not in the CABG group. CONCLUSIONS: LVA can reduce regional afterload and improve ejection performance of the noninfarcted myocardium in many patients with a large anterior LV aneurysm and, moreover, may favorably affect the LV remodeling process after MI.

Cardiac Catheterization↗

Enzyme-linked immunosorbent assay for serological survey of equine arteritis virus in racehorses.

To examine antibodies against equine arteritis virus (EAV), an enzyme-linked immunosorbent assay (ELISA) using purified virus antigen was developed. The results of ELISA were compared with those of serum neutralization (SN) tests. The ELISA absorbance values and the SN titers in sera collected weekly from EAV-infected horses showed a similar pattern. The ELISA could detect antibody to EAV in horses experimentally infected with not only a homologous virus strain, which was used as the ELISA antigen, but also a heterologous strain. Using the ELISA, serum samples collected in 1996 from racehorses in three prefectures (Hokkaido, Ibaraki, and Shiga) were examined and there was no evidence of recent EAV infection among these racehorse populations in Japan. The ELISA should be a simple and highly specific method for rapid screening of EAV infection in racehorses.

Animals↗