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Biomedical subjects

K Fukai

Publications and source records attributed to K Fukai.

At least 109 records · Page 6Linked to original sources
PubMed1986

In vitro secondary generation of cytotoxic T lymphocytes in mice with mumps virus and their mumps-specific cytotoxicity among paramyxoviruses.

Murine cells (L929, MC57G, and P815 mastocytoma) defectively infected with the egg-adapted vaccine strain of mumps virus were found to be susceptible to cytotoxic T-lymphocyte (CTL)-mediated lysis. In vitro secondary, but not in vivo primary, generated CTL caused cytolysis of these targets in an H-2-restricted manner. UV-inactivated-mumps virus-coated murine cells were also found to be susceptible to CTL-mediated lysis. Comparisons of murine CTL-mediated lysis by three paramyxoviruses (mumps, Sendai, and Newcastle disease viruses) indicated that no cross-reactivity occurred. The CTL response with mumps virus exhibited specific unresponsiveness patterns, as influenced by the H-2 K/D regions of the mouse strains, that were partially different from those of Sendai virus and Newcastle disease virus.

Animals↗
PubMed1986

Ascending and descending pathways of reflex straining in the dog.

The location of ascending and descending pathways of the straining reflex was studied by making bulbar cuts in dogs. Rhythmic increases, which were elicited simultaneously in nervous outflows to the diaphragm and rectus abdominis by activation of pelvic afferent fibers, were used to indicate rhythmic straining. The increases were not affected by cutting the dorsal funiculus at the bulbospinal junction, but stopped after cutting both lateral funiculi and by longitudinally cutting the roof of the central canal just caudal to the obex. The increases were impaired by unilateral section of the bulbospinal junction, but were abolished completely after successive ipsilateral hemisection of the rostral bulb. Moreover, rhythmic increases, which appeared synchronously with rhythmic straining in unit discharges recorded from the Kölliker-Fuse nucleus and neighboring structures, disappeared after the longitudinal bulbar cut. However, reflex discharges elicited in pelvic vesical and rectal branches by stimulation of corresponding pelvic afferent fibers were not reduced. These results show that the indispensable part of the ascending pathway of rhythmic straining passes through the lateral funiculus and decussates at the lower bulb, but the pathway of micturition and defecation reflexes do not cross at that level.

Afferent Pathways↗
PubMed1985

A staphylococcal coagglutination test for detecting and serogrouping Legionella pneumophila.

For detection of Legionella pneumophila and determination of its serogroup, the modified staphylococcal coagglutination test was studied in detail. Cross-reactions in serum-agglutination tests were observed among serogroups, but immunoglobulin-coated staphylococcal cells could detect L. pneumophila with high sensitivity (a cell concentration with an absorbance of 0.008 at 660 nm could be detected) and serogroups could be determined without cross-reactions. Moreover the coexistence of other bacteria did not affect the results of the test. These results suggest that the staphylococcal coagglutination test is useful for detection and identification of Legionella, especially in environmental samples, and for serogrouping of isolates of L. pneumophila from clinical specimens.

Agglutination Tests↗
PubMed1985

Three serial neurones in the innervation of the colon by the sacral parasympathetic nerve of the dog.

Electrophysiological and histological techniques were used to study the nature of the innervation of the colon by the sacral parasympathetic nerve of the dog. Many cells which incorporate horseradish peroxidase (HRP) were observed in ganglia of the pelvic plexus, but not in the sacral cord, after HRP was injected into the wall of the distal colon. Stimulation of the pelvic ganglia by an application of dimethylphenylpiperazinium contracted the distal colon. The contraction was reduced by nicotine applied to the colon. Compound action potentials in responses of rectal strands of the pelvic nerve to stimulation of the sacral ventral roots decreased or disappeared after hexamethonium bromide (C6) was applied to the pelvic plexus. Conduction velocities of the potentials showed that most of the preganglionic fibres were B fibres, and nearly all the post-ganglionic fibres were C fibres. Many C fibres were observed by electron microscopy in the rectal strands after degeneration of the pelvic and hypogastric nerves. Stimulation of such rectal strands caused a contraction of the colon, which diminished after C6 was applied to the distal colon. These results show that the sacral parasympathetic nerve innervating the colon comprises three serial neurones located in the sacral spinal cord, the pelvic plexus and the myenteric plexus.

Action Potentials↗
PubMed1985

Demonstration of cholera toxin-related factor in cultures of Aeromonas species by enzyme-linked immunosorbent assay.

The production of toxins by Aeromonas species was examined by the suckling mouse test, the hemolysin test, and the enzyme-linked immunosorbent assay with anticholera enterotoxin. A factor that was immunologically related to cholera enterotoxin was produced by 5 of 14 strains of Aeromonas hydrophila and 4 of 15 strains of Aeromonas sobria. Analysis by these assays and by a test for heat stability suggested that the factor differed from hemolysin and from toxin that was active in the suckling mouse test.

Aeromonas↗
PubMed1985

The afferent and efferent pathways of the recto-colonic reflex in the dog.

The nature of the afferent and efferent pathways of the recto-colonic reflex was studied electrophysiologically in the dog. A compound action potential consisting of many peaks was evoked on a sacral dorsal rootlet by a stimulus to the ipsilateral rectal strands of the pelvic nerve. Conduction velocities of the peaks indicate that A delta and C afferent fibers innervate the colon and rectum. When the stimuli were subthreshold for C fibers, the reflex discharges of contralateral parasympathetic post-ganglionic fibers in the rectal strands and the reflex contraction of the colon were smaller than those caused by stronger stimuli. As the intensity of the stimulus to the sacral ventral roots was weakened, response peaks of preganglionic B fibers in the rectal branch, post-ganglionic C fibers in the rectal strands and a bladder branch of the pelvic nerve disappeared in the order of slow to fast conduction velocities. Contraction of the colon also decreased. The number of peaks arising from each nerve correlated well with the strength of the contraction. These results indicate that the peripheral limbs of the recto-colonic reflex arc consist of afferent A delta and C fibers, preganglionic B fibers and post-ganglionic C fibers.

Action Potentials↗
PubMed1985

Increase of mast cells in the alopecia lesion of mice.

A histological investigation was made of the quantitative behavior of mast cells in bald areas on mice and in human alopecia areata. C57BL,W/Wv and +/+ mice with alopecia lesions were examined. In C57BL mice and +/+ mice, the number of dermal mast cells (per square mm) in the bald areas was greater than that in controls. The mean number of mast cells was slightly higher in human alopecia areata than in the controls. Since W/Wv mice lacking mast cells developed alopecia lesions, it seems that mast cells are not necessary for the onset of alopecia areata but could play some part in regrowth.

Alopecia Areata↗
PubMed1984

Electron microscopic observation of a newly isolated flavivirus-like virus from field-caught mosquitoes.

Of many unidentified virus strains which were isolated from field-caught mosquitoes by using C6/36 cells (a virus-sensitive clone of Aedes albopictus cells), three strains which formed small size plaques (SP virus) in C6/36 cells were investigated by electron microscopy. Although the SP virus strains did not react with antisera against known arboviruses in serological tests, they closely resembled flaviviruses in morphology. However, when they were compared to Japanese encephalitis (JE) virus, several differences in morphogenesis were observed. Proliferating membranous structures and electron-dense amorphous areas involving precursors of the virus were observed only in cells infected with the SP virus strains. Enlarged areas of endoplasmic reticulum containing mature virions were often observed adjacent to these structures. Since the SP virus strains were isolated from wild mosquitoes and multiplied only in mosquito cells, it seems appropriate to classify them as insect viruses which resemble togaviruses morphologically.

Aedes↗
PubMed1984

The intramural pelvic nerves in the colon of dogs.

The intramural pelvic nerves of the dog colon were studied morphologically and electrophysiologically. These nerves emanate from the pelvic plexus, and ascend between the muscle layers along 57.5% of the colon's length. Many thin branches connect with Auerbach's plexus. Most of the nerves responded bilaterally with compound action potentials of A delta and C fibres to stimulation of the sacral dorsal roots, and with those of C fibres to stimulation of the ventral roots. Mean conduction velocities of the A delta and C fibres were 9.0 and 0.9 m/s, respectively. Distension of a section of colon at up to 85.0% of the length of the colon from the anus activated afferent fibres, and electrical stimulation of points at up to 102% of this length elicited responses in efferent fibres. In dogs in which the continuity of the colonic wall was interrupted by a ligature but the nerves were left intact, the intramural pelvic nerves were found to convey centrifugal activities of the recto- and ano-colonic reflexes to the proximal colon, and centripetal and centrifugal activities of the colo-colonic reflex.

Action Potentials↗
PubMed1984

A seroepidemiological study of Japanese encephalitis and dengue virus infections in the Chiang Mai area, Thailand.

As part of a virological and epidemiological survey of encephalitis in the Chiang Mai area, the neutralizing (N) antibody levels of healthy persons to Japanese encephalitis (JE) and dengue (DEN) type 1-4 viruses were examined. A total of 985 blood samples was collected by the filter paper method from subjects of nine age groups in five districts, four (Pasang, Sarapee, Doi Saket and Mae Taeng) in the Chiang Mai Valley and one (Fang) in another valley separated by several ranges of mountains from the Chiang Mai Valley. From analyses of the results of N tests on the specimens, the following conclusions were drawn about the prevalences of JE and DEN viruses in the Chiang Mai area: (1) In the Chiang Mai Valley, the percentage incidences of N antibodies to JE and DEN viruses increased with age and by the age of 15, two thirds or more of the residents had been infected with JE and all DEN viruses except DEN type 2 virus, which showed the lowest prevalence. (2) In the Fang district, the percentage incidence of N antibody to JE virus increased with age, but those to DEN viruses did not, indicating much lower prevalences in the past of all four serotypes of DEN viruses in this district than in the Chiang Mai Valley. (3) At present, most infants in the Chiang Mai area, including the Fang district, seem to be exposed to DEN viruses first and later to JE virus.

Adolescent↗
PubMed1983

The effect of attenuated vaccinia virus AS strain on N-methyl-N'-nitro-N-nitrosoguanidine-induced gastric cancer in rats.

The effect of vaccinia virus on MNNG-induced gastric cancer in rats was studied. Subcutaneous inoculation of the highly attenuated vaccinia virus AS strain at intervals of 3 days from the beginning of the experiment showed prominent antitumor activity not only against adenocarcinoma induced by MNNG in the glandular stomach but also against squamous cell carcinoma in the forestomach. Both UV-inactivated vaccinia virus and the DI strain of mammalian pathogenic vaccinia virus, from which the AS strain originated, showed no antitumor effect.

Adenocarcinoma↗
PubMed1983

Fusion of Sendai viruses or subviral envelope components with chicken erythrocytes observed by freeze-fracture electron microscopy.

Four different types of envelope of Sendai virus or subviral components, that is, infectious and non-infectious virions, reassembled envelope particles (REP), and Tween-ether-treated envelope fragments (TE), were studied comparatively for membrane interactions with chicken erythrocytes by freeze-fracture electron microscopy, specifically for membrane alteration by envelope fusion. The freeze-fracture replicas of the attachment of the four envelopes in the cold exhibited a common pattern of impressions with attached envelopes, although the fracture plane traversed from erythrocyte to envelope at the periphery of the contact areas of three of the envelopes but not of TE, where the fracture plane mostly cut only through erythrocyte membranes impressed with TE. The freeze-fracture replicas of the four envelopes reacting with erythrocytes after a short incubation period at 37 C exhibited distinctive features: infectious virions and REP displayed evidence of envelope fusion, but non-infectious virions and TE showed a particular pattern of envelope association without fusion. Our data demonstrate that the pattern specific for envelope fusion is the formation of a continuous membrane from envelope to cell membrane in a cross fracture of an erythrocyte.

Animals↗