Vaccination with complete adjuvant-added inactivated virus vaccine of Japanese encephalitis to swine, rabbits and chicks for preventing viremia (epidemiological study on Japanese encephalitis 25)

As a step towards the elimination of Japanese encephalitis virus in natural surroundings, we inoculated pigs, rabbits and chicks with inactivated Japanese encephalitis vaccine supplemented with complete or incomplete Freund's adjuvant twice at one-week interval. Subsequently, we compared HI antibody titers of the groups inoculated with vaccine containing complete Freund's adjuvant (pigs, rabbits, chicks), of the group inoculated with vaccine containing incomplete adjuvant (rabbits), ar;d of the groups inoculated with vaccine containing no adjuvant (pigs, rabbits, chicks), and also observations on changes in the antibody titers due to natural infection. In a certain portion of these animals neutralizing antibody titers were also determined. The results of this study are briefly summarized as follows. 1. In the groups of pigs and rabbits inoculated with vaccine containing complete Freund's adjuvant, titers of HI antibody and neutralizing antibody were higher than those inoculated with vaccine containing no adjuvant and their high titers persisted. Further, in the group of chicks inoculated with inactivated Japanese encephalitis vaccine containing complete Freund's adjuvant, HI antibody titers were higher and persistent as compared with the antibody titers in the chicks inoculated with inactivated Japanese encephalitis vaccine alone. 2. In the rabbits inoculated with inactivated Japanese encephalitis vaccine contammg incomplete adjuvant, HI antibody titers were lower than in those receiving the vaccine with complete adjuvant, but it has been demonstrated clearly that vaccination of inactivated Japanese encephalitis vaccine supplemented with incomplete adjuvant brings about less sideeffects. Hence such a method of vaccination can be applied as the vaccination with least side-effects. 3. With respect to natural infection of swine, on August 27 when the pigs were thought to have been infected, there was observed a rise in antibody titers. And on being infected with Japanese encephalitis, the antibodies formed in those pigs inoculated with inactivated Japanese ence- phalitis vaccine with or without complete adjuvant proved to be all 2-ME resistant type, whereas the antibodies produced in the control groups not receiving such a vaccination were 2-ME sensitive antibody.</p

Influence of imipramine on the duration of immobility in chronic forced-swim-stressed rats.

We studied the influence of imipramine on the duration of immobility in chronic forced-swim-stressed rats. Both single and chronic administration of imipramine potently shortened immobility in naive rats during forced-swim testing. However, chronic, 14-day forced-swim stress testing blocked the immobility-decreasing effect induced by a single administration of imipramine. When imipramine was administered for 14 days concurrently with forced-swim stress testing, immobility was shortened significantly. From the viewpoint of imipramine's effect, these findings suggest that chronic forced-swim stress testing in rats may be an effective animal model for depression.</p

Motivational Effects of Nicotine as Measured by the Runway Method Using Priming Stimulation of Intracranial Self-stimulation Behavior

It is well known that priming stimulation promotes the motivational effects of intracranial self-stimulation(ICSS) behavior. An experimental methodology using the runway method could separately study the reward and motivational effects of ICSS behavior. In the present study, we examined the motivational effect of nicotine as measured by the runway method using priming stimulation of ICSS behavior. Electrodes were implanted chronically into the medial forebrain bundle (MFB) in rats. A lever for stimulation of the MFB was set on the opposite side of the start box in the apparatus, and rats were trained to get a reward stimulation (50-200 microA, 0.2 ms, 60 Hz) of MFB when the goal lever was pressed. After the rats were trained to press the lever, a priming stimulation of the MFB was performed. After receiving the priming stimulation, rats were placed at the start box of the runway apparatus, and the running time duration until the goal lever was pressed was measured. Subcutaneous injection of nicotine at a dose of 0.2mg/kg produced an increase in running speed to obtain the reward stimulation, and priming stimulation facilitated the motivational effect to obtain the electrical brain stimulation reward in the rats. These results suggest that nicotine significantly enhanced the motivational effect on ICSS behavior as determined using the runway method. The runway method using priming stimulation of ICSS behavior may become the new experimental methodology with which to measure the motivational effect of some drugs.</p

Transformation of antibody of Japanese encephalitis from IGM to IGG in experimental infected hen and transmission of IGG from hen to chicks. (epidemiological study on Japanese encephalitis. 37)

Transformation of Japanese encephalitis antibody from IgM to IgG in the sera of the experimental infected chicks with Japanese encephalitis virus and transmission of IgM or IgG from hen to chicks were examined by the gel filtration on Sephadex G-200 column. The following results were obtained. 1. Titer of hemoagglutination inhibiting antibody rose on seven days after inoculation of mouse brain homogenate infected with Japanese encephalitis, and that increased rapidly after the second inoculation of Japanese encephalitis. The maximum peak of antibody titer attained on 35 days after the first inoculation, on 7 days after the second inoculation and it maintained for a period of 2 months then decreased. Viremia was detected till 6 hours after the first inoculation. 2. IgM antibody by gel filtration appeared on 7 days after the first inoculation, kept on rising, reached the peak on 35 days after the first inoculation, then decreased, and disappeared on 120 days. IgG antibody appeared about 2 weeks after the IgM antibody appearance, and the titer of IgG antibody became higher than that of IgM antibody on 35 days after the first inoculation, then decreased gradually, and showed 1 : 16 of titer of peak on 150 days by gel filtration. 3. We could obtain the chicks by fertilization from experimentally infected hen, having IgM and IgG of hemoagglutination inhibiting antibody of Japanese encephalitis. And the localization of antibodies in the sera of its chicks was determined by Sephadex G-200 gel filtration. And IgG antibody was detected in chick serum, though IgM antibody was not detected by this method.</p

The Influence of Hyperactivity of the Hypothalamic-pituitary-adrenal Axis and Hyperglycemia on the 5-HT2A Receptor-mediated Wet-dog Shake Responses in Rats

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis induces hyperglycemia and serotonin (5-HT)2A receptor supersensitivity. In the present study, to investigate the effect of hyperglycemia on the function of 5-HT2A receptors, we compared the 5-HT2A receptor-mediated wet-dog shake responses in rats treated with adrenocorticotropic hormone (ACTH), dexamethasone and streptozotocin. ACTH (100 &#956;g/rat per day, s.c.), dexamethasone (1 mg/kg per day, s.c.) and streptozotocin (60 mg/kg, i.p.) produced significant hyperglycemia at 14 days after the start of these treatments, and the hyperglycemia was most pronounced in the streptozotocin-treated rats. The wet-dog shake responses induced by (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), a 5-HT2A receptor agonist, were significantly enhanced at 14 days after repeated treatment with ACTH and dexamethasone. However, streptozotocin-induced diabetes had no effect on the wet-dog shake responses. The results of the present study suggest that hyperglycemia is not strongly associated with the enhanced susceptibility of 5-HT2A receptors under the condition of hyperactivity of the HPA axis.</p

Infection of herons and domestic fowls with Japanese encephalitis virus with specific reference to maternal antibody of hen (epidemiological study on Japanese encephalitis 26

In order to ascertain whether black-crowned night herons (BCNH), white heron (Plumed Egrets (PE)) and domestic fowls are infected by JE virus and they serve as infection source ofJE, hemoagglutination inhibiting antibody and its 2·ME sensitive antibody in the sera of these birds were determined. Physico-chemical nature of fowl's antibody of JE produced by natural infection and their maternal antibody in the sera of chicks were examined. The results are briefly summarized as follows. 1) As to the herons captured in Tsudaka Town, two out of six adult night herons and three out of the four chicks showed positive HI reaction. On the other hand, HI reaction in the sera of two adult white herons and three chicks were negative. 2) As to the herons captured in Okayama City, twenty out of thirtytwo adult night herons and seven out of seventy white herons showed positive HI reaction in 1966 around the time when JE was prevalent in Okayama Prefecture. And six out of eleven night herons and one out of seven white herons showing positive HI reaction, responded positively to 2-ME sensitivity test. 3) The results indicate that white herons can be also infection source ofJE though less than in the case of night herons. 4) In the domestic fowls (white leghorn) kept at Takahashi District, eight out of twenty-seven fowls showed positive HI reaction. And six out of seven domestic fowls showing positive HI reaction responded positively to 2-ME sensitive reaction. 5) Transformation of JE antibody in the serum of hen from IgM to IgG was recognized. 6) Domestic chicken's sera having 1 : 640 of HI titer in the original serum and 1 : 320 of HI titer after 2-ME treatment were fractionated by gel filtration on Sephadex G-200 and the antibody activities present in the various fractions were determined. HI antibody activities occurred in both IgM and IgG classes of immunoglobulins. 7) Maternal HI antibodies reacting with JE virus were found in newly hatched domestic chickens from the eggs laid by hens with natural infection ofJE. And half life of HI antibodies in chicks was four days. 8) HI antibodies of JE in the serum of maternal immune-hens and chicken having maternal antibody were located in r-globulin fraction by starch block electrophoresis. 9) The results from 4) to 8) indicate the presence of natural infection ofJE in the domestic fowls. And domestic fowls can be infection source ofJE.</p

Vaccination with complete adjuvant-added inactivated virus vaccine of Japanese encephalitis to swine for preventing viremia (with specific reference to the effect of vaccination on viremia; epidemiological study on Japanese encephalitis. 35)

As to trial toward the elimination of Japanese encephalitis virus in natural surroundings, pigs received inoculation of inactivated Japanese encephalitis vaccine supplemented with complete Freund's adjuvant twice at one-week interval. Effect of adjuvant supplement on the magnitude of antibody and also prevention of viremia caused by natural infection by antibody induced with vaccine were investigated. The results of this study are summarized as follows. 1. In the group of pigs inoculated with vaccine containing adjuvant, titer of hemoagglutination inhibiting and neutralizing antibodies was higher than those inoculated with vaccine alone and their high titer persisted. 2. With respect to natural infection of pigs, on August 22 when the pigs were thought to have been infected, there was observed a rise in antibody titers. And on antibody formed in those pigs inoculated with vaccine with or without adjuvant proved to be all 2-ME resistant type, whereas the antibodies produced in control group were 2-ME sensitive antibody. 3. Viremia was detected in the blood of pigs naturally infected, but it was not demonstrated pigs inoculated with vaccine supplemented with adjuvant or without adjuvant. The virus of pig blood which was inoculated into suckling mouse brain and was separated after low suckling passage mouse was supposed to be JaGAr strain from optimum hydrogen ion concentration of its hemoagglutination reaction. 4. Effect of vaccination on antibody response of pigs having maternal antibody was not recognized.</p