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Biomedical subjects

T Mikami

Publications and source records attributed to T Mikami.

At least 811 records · Page 45Linked to original sources
PubMedDate not supplied

Feasibility of a nickel-metal hydride battery for totally implantable artificial hearts.

An implantable rechargeable battery is one of the key technologies for totally implantable artificial hearts. The nickel-metal hydride (Ni-MH) battery is promising for its high energy density of 1.5-2.0 times that of a nickel-cadmium battery. In this study, the effects of pulsatile discharge loads on the operating time and cycle life of Ni-MH batteries at 39 degrees C were studied. Two battery cells (TH-3M, 1,200 mAh, phi 14.5 x 49 mm; Toshiba, Tokyo, Japan) in series were charge/discharge cycled at 39 degrees C using a charge current of 1CA (1,200 mA) and then were fully discharged to 1.0 V/cell under either pulsatile discharge loads, which mimicked a systole (1 A for 0.3 sec) and a diastole (0.4 A for 0.3 sec), or a non pulsatile discharge load equivalent to the average of the pulsatile loads (0.7 A). Each cycle life test was interrupted on the 482nd cycle under pulsatile load, and on the 423rd cycle under non pulsatile load, because of malfunction of each battery charger. The tests showed that the pulsatile discharge cells had significantly (p < 0.001) less operating time (74.0 +/- 7.15 min) throughout the test period (up to 482 days) compared to the cells under equivalent non pulsatile discharge loads (93.7 +/- 7.74 min). The pulsatile-discharged Ni-MH cells provide significantly less operating time than the constantly discharged cells; the Ni-MH battery has an operating time of over 78 min and a cycle life of almost 500 cycles at 39 degrees C. In conclusion, the Ni-MH battery is feasible as an implantable back-up battery for a totally implantable artificial heart system.

Electronics, Medical↗
PubMedDate not supplied

Effects of Si-functional isocyanate on the stability of oil-in-water emulsion with and without a carbon functional isocyanate.

The effects of silicon-functional isocyanates on the stability of oil-in-water emulsions with and without a carbon functional triisocyanate in the oil phase were investigated. The oil component was di-n-butyl-phthalate (DBP) containing Aerosol OT as an emulsifier. It was found that only CH3Si(NCO)3 among the (CH3)nSi(NCO)4 - n's was effective to contribute additional stability for the emulsion without a carbon functional triisocyanate. It was also found that a reaction product of CH3Si(NCO)3 with water reacted with a carbon functional triisocyanate.

Dibutyl Phthalate↗
PubMedDate not supplied

Effects of diethylenetriamine and Aerosol OT on the stability of oil-in-water emulsion stabilized by interfacial polyurea film.

The stability of oil-in-water emulsions containing a triisocyanate soluble in the oil phase and an amine in the water phase was investigated. The oil component was di-n-butyl phthalate (DBP) containing Aerosol OT as an emulsifier. The time required for the average size parameter to reach a constant value was studied. It was found that the polyurea film produced by an interfacial polymerization reaction between the amine and the triisocyanate contributed to forming a stable emulsion at a lower Aerosol OT concentration, but at a higher Aerosol OT concentration the amine did not show any effect on the emulsion stability.

Chemical Phenomena↗
PubMedDate not supplied

The origin of extragonadal teratoma: case report of an immature teratoma occurring in a prenatal brain.

We describe a massive congenital intracranial teratoma (MCIT), which had a normal chromosome banding pattern 46,XY karyotype and a normal diploid DNA histogram, and which produced a variety of carcinoembryonic antigens. The volume density of primitive neural components (primitive neural tubes, small undifferentiated neuroepithelial cells, immature glial fibers and pigment cell components without neurofibrillar differentiation) was estimated to be 45%. We discuss the histogenesis, pathobiology and cell cycle kinetics.

Adult↗
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MDV glycoprotein D is expressed in the feather follicle epithelium of infected chickens.

Glycoprotein D (gD) and its homologues are essential for many alphaherpesvirus life cycles. A gene encoding a homologue of gD was recently found in the Marek's disease virus (MDV) genome. Interestingly, gD-negative MDV mutants apparently replicate unimpaired in both cell culture and chickens. In this study, we show the expression of the gD homologue of MDV in feather follicle epithelium in infected birds. The gD homologue was detected in a few feather follicles even when most of the follicles were expressing pp38 or gB, other MDV-specific proteins. These observations indicate that the MDV gD homologue is expressed in a very limited set of cells and may be differently regulated. Since feather follicle epithelium of infected birds are the only place where the infectious cell-free MDV virions can be recovered, analysis of the transcriptional regulation of gD may lead to the understanding of the cell-associated nature of MDV.

Animals↗
PubMedDate not supplied

Reticulin fiber staining of crush preparations for the rapid differentiation between schwannomas and meningiomas.

The use of reticulin fiber staining of cytologic crush preparations for the rapid differentiation of schwannomas and meningiomas of the cerebellopontine angle was studied. As in paraffin-embedded sections, the reticulin stain demonstrated distinctly different patterns in the two types of tumors. Schwannomas showed extremely numerous, uniformly delicate straight fibers in a streaming or interlacing pattern in cellular areas and less dense, more wavy or curly fibers in degenerative areas. Fibroblastic meningiomas showed a few loose fibers of variable thickness in a root-like tangle while meningotheliomatous meningiomas showed no fibers, except in areas of fibrovascular stroma; both types showed small scattered round structures made up of reticulin fibers. These findings suggest that reticulin staining of crush preparations should be performed as an adjunct to routine cytologic staining of crush preparations and the study of frozen sections in making the intraoperative diagnosis of these tumors.

Cerebellar Neoplasms↗
PubMedDate not supplied

Isolation of serotype 2 Marek's disease virus from birds belonging to genus Gallus in Japan.

Serotype 2 of Marek's disease virus (MDV) was isolated from apparently healthy birds belonging to genus Gallus that had no history of vaccination with MDV or herpesvirus of turkeys (HVT). Buffy-coat cells from these birds were inoculated onto chicken embryo fibroblast (CEF) cultures for primary isolation. Thirteen isolates from one golden pheasant and three white silky fowls, three black silky fowls, three Japanese long crowers, and three Japanese bantams produced herpes-like cytopathic effects (CPE) in the CEF cultures. Using serotype-specific monoclonal antibodies to MDV and HVT, 11 isolates were identified as serotype 2 MDV by indirect fluorescent antibody tests. The other two isolates were complicated with serotypes 1 and 3 of MDV-related viruses. Of 13 isolates, three cloned by the limiting-dilution method were further characterized as serotype 2 MDV biologically, genetically, and serologically. The results showed that the birds of the genus Gallus were naturally infected with serotype 2 MDV. This is the first report ever published about the distribution of serotype 2 MDV among healthy birds of the genus Gallus.

Animals↗
PubMedDate not supplied

Detection of fowlpox virus DNA by in situ hybridization using a biotinylated probe.

In situ hybridization was applied to detect fowlpox virus (FPV) DNA in formalin-fixed paraffin-embedded sections of the skin from infected chickens by using a biotinylated probe and a streptavidin-alkalinephosphatase conjugate. The immunohistochemical examination was applied to compare the distribution of the FPV DNA to that of related antigenic protein in serial sections. In the infected epithelial cells, FPV DNA was detected in cytoplasmic inclusion bodies and in the rest of cytoplasm. Likewise, immunohistochemical examination revealed the virus antigen in cytoplasm. Ultrastructurally, virions were observed in the cytoplasmic inclusion bodies, and immature virus particles were in the rest of the cytoplasm. The study proved restricted distribution of FPV DNA in the cytoplasm.

Animals↗
PubMedDate not supplied

A transcutaneous optical information transmission system for implantable motor-driven artificial hearts.

Precise regulation of output voltage (motor voltage) and monitoring of the implanted pump were obtained with a transcutaneous energy transmission system. Information on both motor voltage and pump stroke is transmitted through the skin by frequency-modulated infrared pulses using a light emitting diode and a phototransistor. The motor voltage is compared with the nominal value, and the duty cycle of the primary pulse is regulated according to the error signal. Infrared pulses up to 100 KHz were transmitted through porcine muscle up to 1 cm thick. Both the pump stroke and motor voltage signals were transferred across the muscle without interference. The output voltage was kept almost constant for the change in tissue gap of 3-8 mm and of 0-10 mm in radial displacement. The system developed is useful for implantable artificial hearts.

Electric Conductivity↗
PubMedDate not supplied

Complement-dependent antibody cytotoxicity test of chicken antibody with duck complement used against cells of a Marek's disease lymphoma-derived cell line (MSB-1).

Complement-dependent antibody cytotoxicity (CDAC) against cells of a lymphoblastoid cell line (MSB-1) derived from Marek's disease lymphoma was investigated in a chicken antibody system using complements from several animal species. Cytotoxicity was seldom observed when rabbit, guinea pig, or chicken complements were used in the presence of hyperimmune chicken serum against MSB-1. With duck complement, however, cytotoxicity was always observed. Therefore, duck complement appears to be suitable for assay of hyperimmune chicken serum against MSB-1 cells by the CDAC test.

Animals↗
PubMedDate not supplied

Cytoprotective action of roxatidine acetate HCl.

The cytoprotective action of roxatidine acetate HCl (roxatidine) was investigated. We also studied the involvement of endogenous prostaglandins (PGs) in the cytoprotective action of roxatidine and the effect of roxatidine on SRS content in pleurisy induced by A23187. Simultaneously, these effects of roxatidine were compared with those of other histamine H2-receptor antagonists at the same anti-secretory activity level. Roxatidine prevented formation of the gastric mucosal lesions induced by abs. ethanol, 0.6 N HCl and 0.2 N NaOH, but it failed to prevent 30% NaCl-induced gastric mucosal lesions. Cimetidine, ranitidine and famotidine failed to prevent formation of the gastric mucosal lesions induced by necrotizing agents. The cytoprotective action of roxatidine was not abolished by pretreatment with indomethacin. Roxatidine did not greatly influence SRS production. Consequently, it appears that roxatidine has a cytoprotective action and that this action is not associated with endogenous PGs and SRS.

Animals↗
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Serological and pathological studies of Newcastle disease viruses isolated from caged birds from Southeast Asia.

Eleven isolates of Newcastle disease virus (NDV), from caged birds imported from or captured in Southeast Asia in 1979-80, were antigenically divided into five distinct groups. Most of them were distinguishable from more classical NDVs (vaccine B1 strain and Miyadera strain) on the basis of their reactivity to eight monoclonal antibodies against the HN molecule of NDV in hemagglutination-inhibition tests. However, when three representative isolates were evaluated for their biological properties and pathogenicity against 1-day-old chickens, all three were found to be velogenic types that could induce serious symptoms of Newcastle disease and which eventually killed all of the chickens, regardless of the route of infection. There was not any significant correlation between their reactivity patterns with the monoclonal antibodies and their virulence.

Animals↗
PubMedDate not supplied

Feather-pulp lesions in chickens with naturally occurring Marek's disease lymphomas.

Feather pulps of 15-to-35-week-old chickens with Marek's disease (MD) lymphomas were examined histopathologically. Of the 64 chickens, 59 (92.2%) had lymphoproliferative (T-type) lesions in the feather pulp. The T-type feather-pulp lesion (FPL) occurred in all regions, but more frequently in the upper column of the pulp. Severe lesions were distributed throughout the feather pulp. Some of the T-type FPLs regressed to inflammatory lesions consisting of necrosis or loss of constituent cells, edema, and infiltration by small lymphocytes, heterophils, and plasma cells. The regressive T-type FPL was usually diffuse throughout the tumorous lesions, but proliferative foci were often seen concomitantly with regressive lesions. The grade and histologic picture of T-type FPLs in chickens correlated well with those of the visceral lymphomas. These findings suggest that the severity of MD lymphoma is predictable without autopsy by examining feather-pulp samples.

Animals↗
PubMedDate not supplied

A study of Marek's disease in Japanese quails vaccinated with herpesvirus of turkeys.

In a study of outbreaks of Marek's disease in quails, 220 adult quails vaccinated with herpesvirus of turkeys (HVT) were examined pathologically and serologically for Marek's disease (MD). Forty-three of the 220 quails exhibited microscopic lesions similar to those of chickens with MD. MD-virus-specific antigen was found in feather tips of 44 of the 220 birds, and the HVT-specific antibody was found in sera of 56 of the 220 birds by agar gel precipitation. There was a positive correlation between the incidence of lymphomatous changes and the presence of MD-virus-specific antigen, and there was a negative correlation between the incidence of lymphomatous changes and the presence of antibody against HVT on a flock basis.

Animals↗
PubMedDate not supplied

Inhibition of turkey herpesvirus replication by anti-cellular serum.

Quail embryo fibroblasts were used to investigate how rabbit and chicken antisera against chicken erythrocytes carrying different B alleles of the major histocompatibility antigens affect the neutralization of herpesvirus of turkeys (HVT). Although the neutralizing activities of these antisera were rather low, the HVT propagated in chicken embryo fibroblasts (CEF) from certain genotypic embryos was neutralized more by the antisera to the corresponding erythrocytes. After absorption of these antisera with homologous erythrocytes, the neutralizing activity of the absorbed sera was reduced slightly. These results reveal that the virion antigens of HVT might be partially associated with the host cell antigens of the fibroblast infected with the virus. The virus grown in these cells might incorporate the host cell antigens, including histocompatibility antigens, into the virion envelope.

Animals↗