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Biomedical subjects

K Fukai

Publications and source records attributed to K Fukai.

At least 91 records · Page 5Linked to original sources
PubMed1988

Protection against Japanese encephalitis by inactivated vaccines.

Encephalitis caused by Japanese encephalitis virus occurs in annual epidemics throughout Asia, making it the principal cause of epidemic viral encephalitis in the world. No currently available vaccine has demonstrated efficacy in preventing this disease in a controlled trial. We performed a placebo-controlled, blinded, randomized trial in a northern Thai province, with two doses of monovalent (Nakayama strain) or bivalent (Nakayama plus Beijing strains) inactivated, purified Japanese encephalitis vaccine made from whole virus derived from mouse brain. We examined the effect of these vaccines on the incidence and severity of Japanese encephalitis and dengue hemorrhagic fever, a disease caused by a closely related flavivirus. Between November 1984 and March 1985, 65,224 children received two doses of monovalent Japanese encephalitis vaccine (n = 21,628), bivalent Japanese encephalitis vaccine (n = 22,080), or tetanus toxoid placebo (n = 21,516), with only minor side effects. The cumulative attack rate for encephalitis due to Japanese encephalitis virus was 51 per 100,000 in the placebo group and 5 per 100,000 in each vaccine group. The efficacy in both vaccine groups combined was 91 percent (95 percent confidence interval, 70 to 97 percent). Attack rates for dengue hemorrhagic fever declined, but not significantly. The severity of cases of dengue was also reduced. We conclude that two doses of inactivated Japanese encephalitis vaccine, either monovalent or bivalent, protect against encephalitis due to Japanese encephalitis virus and may have a limited beneficial effect on the severity of dengue hemorrhagic fever.

Adolescent↗
PubMed1988

Discharges of bulbar respiratory neurons during rhythmic straining evoked by activation of pelvic afferent fibers in dogs.

Each cycle of rhythmic straining evoked through the reflex center in the Kölliker-Fuse nucleus by stimulation of pelvic afferents in decerebrate dogs usually began in early expiration. During the rhythmic straining cycle, postinspiratory discharges of the phrenic nerve increased simultaneously with a burst of discharges of the nerves innervating the rectus abdominis and adductors of the glottis. While about half of the bulbar expiratory units discharged concurrently with the rhythmic straining, almost none of the inspiratory units examined did so. Nearly all expiratory bulbospinal units discharged concurrently, but none of the inspiratory bulbospinal units did so. These results show that expiratory neurons in the caudal bulb relay commands for rhythmic straining from the pontine reflex center to motor neurons of expiratory muscles, but that bulbar inspiratory neurons do not relay the commands to inspiratory motor neurons. Discharges concurrent with rhythmic straining were also evoked in all 4 postinspiratory units of the ventral group, 3 very early onset expiratory units and all 9 inspiratory-expiratory units of the dorsal group. Possible roles played by these respiratory neurons in the organization of rhythmic straining were discussed.

Afferent Pathways↗
PubMed1988

Immunohistochemical localization of type V collagen in normal human skin.

Tissue distribution of type V collagen in normal human skin was studied using an indirect immunofluorescent technique to determine whether type V collagen is present in the interstitium or in the basement membrane. Type V collagen was isolated from the human placenta by pepsin digestion and was purified with fractioning salt precipitations. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that type V collagen contained alpha 1(V) and alpha 2(V) chains, but not the alpha 3(V) chain. Specificity of the rabbit antibodies to type V collagen was assessed using enzyme-linked immunosorbent assay (ELISA) and an immunoblotting method. Antibodies showed no cross-reactivity to other collagens, laminin, and fibronectin. With an indirect immunofluorescent technique, type V collagen was found to be widely distributed throughout the dermis. Intense fluorescent staining was noted in the papillary dermis and adnexal dermis surrounding hair follicles and eccrine glands. The basement membrane of the dermoepidermal junction, skin appendages, and capillaries was not stained. By indirect immunoperoxidase double staining, type V collagen was not found to be deposited on type IV collagen present in the basement membrane. Immunoelectron microscopic studies showed that type V collagen was not located in the basal lamina. These results suggest that type V collagen is distributed in the interstitium, but not in the basement membrane of normal human skin.

Adult↗
PubMed1988

The purification and characterization of an acellular pertussis vaccine.

An acellular pertussis vaccine manufactured by Biken was investigated for purity, potency and toxicity. The vaccine was composed of almost equal proportions of pertussis toxin (PT) and filamentous hemagglutinin (FHA). The purity of the vaccine was 97-99%. The protective effects of component vaccines containing various ratios of PT and FHA were tested and it was found that the ratio of 1:1 provided the most effective vaccine.

Animals↗
PubMed1988

Development of inactivated vaccine against virus causing haemorrhagic fever with renal syndrome.

B-1 virus belonging to the hantavirus group was serially passaged in the brains of newborn mice. Inactivated vaccine was prepared from the brains after inactivation with formalin and then purification by ultracentrifugation. The antigenic potency of this vaccine in vitro was determined by antibody-bound enzyme-linked immunosorbent assay (ELISA) and serial diluted vaccine bound to an aluminium hydroxide gel was inoculated into Balb/c mice to test immunogenicity. After two injections of this vaccine preparation, antibodies were detected in the mice by immunofluorescent, neutralizing and haemagglutination inhibition antibody tests. When mice immunized with this vaccine were challenged with B-1 virus and Hantaan virus (KHF-83-61BL strain), the virus titres in their lungs and spleens were significantly less than those in non-immunized mice. These results suggest that inactivated B-1 virus vaccine is effective against virus challenge by homotypic (B-1 virus) and heterotypic (Hantaan virus) viruses.

Animals↗
PubMed1988

[Periodontal surgical approach to the vertical fracture of the root. The application of composite resin to the fractured root surface].

For a patient who had a deep periodontal pocket without an attached gingiva on labial central area of left upper canine, a free gingival graft from the palate was done. After that, a flap was reflected and the cause of the lesion was determined. It became clear that there was a vertical fracture of the root and a composite resin (Clearfil-SC) was used to fill the fractured area. It has been 2 1/2 years since the therapy and the prognosis is good.

Gingiva↗
PubMed1988

Immunofluorescent localization of type I and III collagens in normal human skin with polyclonal and monoclonal antibodies.

Anti-type I and type III collagen polyclonal antibodies and anti-type III collagen monoclonal antibodies were produced using type I and type III collagen extracted from the human placenta. An indirect immunofluorescence technique using these antibodies showed the same distribution of type III as well as type I collagen in the entire dermis of the normal human skin in nearly identical patterns. Previous immunofluorescent study indicated that type III collagen is present predominantly in the papillary dermis. However, our observation that monoclonal antibody recognizing the helical portion of type III collagen reacted with the entire thickness of the dermis which suggested the presence of type I and III collagen in close proximity in the whole thickness of normal human dermis.

Adolescent↗
PubMed1988

Efficacy of acellular pertussis vaccine in Japan--comparison of two areas, one area where immunization started at 6 months and the other area at over 2 years of age--Regional Surveillance Committee on Tuberculosis and Infectious Diseases of Osaka.

In the Osaka area, a very satisfactory surveillance system of infectious diseases has been achieved with the establishment of a weekly facsimile network, and computer aided graphics and feedback system. A mathematical formula has been devised for calculating the number of reported cases in exactly 100,000 of the population using the constant reported number of cases of exanthema subitum every week. With this method, we compared the incidence of pertussis patients in two areas, one where acellular pertussis vaccine is given to children after 6 months of age and the other where it is given at more than 2 years of age. The former area has the one fifth the incidence of pertussis patients of the latter.

Age Factors↗
PubMed1987

Cold-adaptation of human rotavirus.

A human rotavirus strain was cold-adapted for possible future use as a live vaccine. The original strain was isolated in 1980 in primary cynomolgus monkey kidney cells and has a serotype I and subgroup II antigenicity. The virus was serially passaged in African green monkey kidney cells; it was cultivated at 37 degrees C at the first stage of passages, and the cultivation temperature was then shifted down stepwise by 3 degrees C per each 10 passages. Finally the virus was passaged 10 times at 25 degrees C (total passage number of 55). The virus formed small-size plaques with irregular shaped borders at 31 degrees C. Growth at 25 degrees C of the cold-adapted virus was higher than that of the original virus. There was no difference between the migration patterns of 11 dsRNA segments in polyacrylamide gel electrophoresis of the original and the cold-adapted viruses.

Adaptation, Physiological↗
PubMed1987

Reflex responses of neurons in the inferior mesenteric ganglion to mechanical stimulation of the colon, rectum, anal canal, and urinary bladder in the dog.

Unitary discharges were recorded from the inferior mesenteric ganglion of decerebrate dogs. Eighty-one units were identified as sympathetic postganglionic neurons innervating the colon and rectum by collision test performed by stimulation of the lumbar colonic nerve. Discharges of four units were enhanced simultaneously with an increased outflow of the renal nerve by pinching a toe. Thus, those units were regarded as vasoconstrictors of colonic blood vessels. Sixty-five units whose discharges were depressed or not affected by the pinching were regarded as neurons innervating colonic smooth muscle or mucosa (colonic units). Discharges were enhanced in the majority of the colonic units by colonic, rectal, and vesical distension, and mechanical stimulation of the anal canal, while discharges were depressed in a few units by rectal and vesical distension, and the anal canal stimulation. The number and percentage of the depressed units increased not only after cutting the hypogastric nerves and descending branches of the lumbar colonic nerve but also after transection of the caudal pons. The reflex depressions disappeared after transection at the bulbospinal junction, but the reflex enhancements remained. These results indicate that the colonic units are enhanced through a spinal reflex by the inflows from the distal colon, rectum, anal canal, and urinary bladder through the lumbar colonic, hypogastric, pelvic, and pudendal nerves, while a few are inhibited through a supraspinal reflex by inflows through the pelvic and pudendal nerves.

Action Potentials↗
PubMed1987

Studies in the development of Japanese encephalitis vaccine: expression of virus envelope glycoprotein V3 (E) gene in yeast.

A safe, effective and economical vaccine is required for the prevention of Japanese encephalitis (JE), a disease with high mortality and grave sequelae, which is prevalent in Japan and other countries in east, south-east and southern Asia. As the initial step to produce a second-generation vaccine, recombinant DNA technology was utilized to express the JE virus envelope glycoprotein V3 (E) gene in yeast cells.This report describes the construction of a yeast expression vector in which a cDNA clone covering the V3 gene was connected to the acid-phosphatase promoter of a yeast vector plasmid. Successful expression of the V3 gene was detected by ELISA and Western blotting using monoclonal antibodies against JE V3. Immunization of mice with the V3 antigen expressed in yeast produced limited but definite levels of anti-JE antibodies which could neutralize JE virus. The results are an encouraging step in the development of a practical second-generation JE vaccine.

DNA, Recombinant↗
PubMed1986

Postural change and straining induced by distension of the rectum, vagina and urinary bladder of decerebrate dogs.

In decerebrate dogs, stimulation of pelvic afferent fibres and distension of the rectum, vagina and urinary bladder brought about a sustained postural change and rhythmic abdominal compression. The posture, which resulted from flexion of the back and stifle joints, extension of the hip joints and lifting of the tail, was rhythmically intensified with the abdominal compression. The sustained and rhythmic postural changes are similar to those observed in conscious dogs during defaecation. Intratracheal pressure increased with the abdominal compression. Nervous outflow to the muscles of the glottis, diaphragm, abdominal wall, tail and rear legs changed as would be expected from both the postural changes and the increases in intratracheal and intra-abdominal pressure. Nervous outflow to the external sphincter muscles of the anus and urethra increased simultaneously with both kinds of postural change; however, the increased outflow to the anus was suppressed when defaecation was initiated, and the outflow to the urethra was suppressed when micturition was initiated. In about one-third of the dogs, decreases in the outflow of the pelvic rectal branch and slight increases in the outflow of the vesical branch occurred synchronously with the abdominal compression. These results show that postural change and straining for defaecation, micturition and parturition are reflexly organized by the lower brainstem and the spinal cord.

Action Potentials↗
PubMed1986

Location of the reflex centre for straining elicited by activation of pelvic afferent fibres of decerebrate dogs.

The reflex centres for straining for defaecation, micturition and presumably for parturition were located electrophysiologically in decerebrate dogs. Stimulation of pelvic afferent fibres initially induced a sustained increase in nervous outflow to the diaphragm, rectus abdominis and lateral cricoarytenoid muscles and subsequently induced rhythmic increases which were superimposed on the sustained increase. The rhythmic increases occurred even after transection at the most rostral pons, but they were abolished by a partial cut at the most lateral part of the rostral pons following transection of the contralateral half of the rostral medulla oblongata. The sustained increase continued after transection 1.5 mm caudal to the obex, but disappeared after transection about 5 mm caudal to the obex. This result shows that straining is brought about by both sustained and rhythmic straining reflexes. Both sustained and rhythmic straining, but not defaecation and micturition, could be elicited by stimulation of an area of the Kölliker-Fuse nucleus. The discharges of about half of the units in the nucleus and the neighbouring rostrolateral pontine area which responded to stimulation of the pelvic afferent fibres changed synchronously with the rhythmic straining. These results show that the rhythmic and sustained straining reflex centres are located in the Kölliker-Fuse nucleus and in the lower medulla oblongata, respectively.

Animals↗
PubMed1986

Trial of inactivated Japanese encephalitis vaccine in children with underlying diseases.

Two shots of inactivated Japanese encephalitis (JE) vaccine were given to children, 139 with underlying diseases and 42 healthy, and their antibody responses were studied by the neutralization test. Before vaccination, most of the vaccinees did not have antibody against JE virus. One month after the second vaccination, they were all seroconverted and showed considerably high neutralizing titres. One healthy child developed fever on the day of vaccination without any severe symptoms afterwards, and no side reactions were observed in the handicapped children. These results suggest that the current JE vaccine is safe and can induce a strong immune response even in handicapped children.

Antibodies, Viral↗