Characterization of very virulent Marek's disease viruses isolated in Japan

Pathogenicity of two isolates of Marek's disease virus (MDV), MS1 and MS2, from chickens was examined in two genetically different strains of chickens, MD-susceptible P-2 chickens and less susceptible PDL-1 chickens. The isolates induced an early mortality syndrome unassociated with lymphoproliferative lesions in P-2 chickens. There were no significant differences in pathogenicity between our isolates and the Md/5 strain of very virulent MDV (vvMDV) in both P-2 and PDL-1 chickens. Protective indices of turkey herpes virus (HVT) vaccine against challenge with MS1 or MS2 in P-2 chickens were 54% and 28%, respectively, whereas HVT gave more than 80% protection in PDL-1 chickens. These results indicate that the two isolates could be classified as vvMDV. In contrast, a bivalent vaccine composed of HVT and serotype 2 MDV, and CVI988 vaccine gave good protection against challenge with the isolates in P-2 chickens; however, the best protection was given by the CBI988 vaccine. This is the first report of isolation of vvMDV in Japan.     

9株YONBAN相关TTV变异株全基因序列测定及其结构、分型的研究

目的：对9个TTV新分离株全基因序列测定，基因结构及基因分型的研究。方法：从9名TTV第4基因群感染阳性的婴儿血清中抽提取其DNA，用long inverted PCR扩增出全基因组，克隆和测定全基因组序列，并对测序结果进行计算机分析。结果：首次次测定了TTV第4基因群共9个新分离株的全基因序列，其中8个分离株代表核基因群首次报道的8个新基因型。结论：TTV基因组核酸序列具有高度异质性及基因型的高度多样性，但是，其独特的转录特性和基因组的基本结构在各自的基因群及基因型中十分保守。     

Functional CD4+T cell subsets defined by expression of CD45RC and NTA260 antigens and age-associated polarization in murine lupus

Using two mAb, one specific to the alternative exon 6-dependentepitope of CD45 molecules(JH6.2) and one a natural thymocytotoxicautoantibody (NTA) with an unknown reactive epitope (NTA260),we subdivided splenic CD4⁺ T cells from 2-month-old BALB/c miceinto five phenotypically distinct subsets. CD45RC⁺NTA260^–(SI) cells were phenotypically analogous to CD4⁺ T cells predominatingin newborn mice and produced a significant amount of IL-2, butnot so IL-4, IL-10 or IFN- when stimulated with immobilizedanti-CD3 mAb in vitro. They appeared to consist mainly of naiveT_hP cells. The CD45RC⁺;NTA260⁺ (S II) subset also produced IL-2,but not other cytokines; however, the IL-2 levels produced weremuch higher than seen with the S I subset, thereby suggestingthe predominance of further maturated T_hP cells. The D45RC^–NTA260⁺(S III) subset mainly produced IL-4, IL-10, IFN- and less IL-2,and contained memory cells that helped the secondary antibodyresponse to a recall antigen, and hence contained T_h2 and probablya mixture of T_h0 and T_h1 cells. The CD45RC^–NTA260^–(S IV) subset was a poor responder to the immobilized anti-CD3mAb. The CD45RC^brightNTA260^dull(S V) subset consisted of a smallnumber of cells that were phenotypically analogous to activatedCD4⁺ T cells. While an age-associated decrease in the proportionof S I and less markedly in S II and in turn increase in S IIIsubsets of CD4⁺ T cells occurred in normal BALB/c mice, autoimmunedisease-prone (NZBxNZW)F₁ mice showed a marked age-associateddecrease in the proportion of not only S I, II but also IIIsubsets. As aged (NZBxNZW)F₁ mice carry CD4⁺ T helper cellsfor IgG anti-DNA antibody production, such age-associated polarizationto the S IV subset appears to be critical in the pathogeneslsof autoimmune disease in these mice.     

Study on the mechanism of the appearance of noise effects

Summary This study was undertaken to investigate the dose-response relationship between the biological effect and noise exposure, and to consider the mechanism of the appearance of noise effects. Rats were exposed to noise at intensities of 60 dB (A), 80 dB (A) and 100 dB (A) for 240 min and examined for the change of activities of dopamine--hydroxylase (DBH) in serum and adrenal glands. Plasma cyclic adenosine 3,5-monophosphate (c-AMP) levels were also measured. Some rats were given 6-hydroxydopamine (6-OHDA) as a chemical sympathectomyzing agent 20 h before noise exposure in order to consider the mechanism of the appearance of noise effects. By noise exposure, serum DBH activity was significantly (P<0.01) increased at each intensity compared with the control group, but there were no remarkable changes in adrenal DBH activity. Plasma c-AMP level was also significantly elevated in response to the noise stress. When the rats, which had been pretreated with 6-OHDA, were exposed to noise with an intensity of 100 dB (A), the response of serum DBH activity was no longer observed. Therefore it is suggested that the effect due to noise exposure appears through the post-ganglionic sympathetic nerve fiber.     

Antigenicity of cryopreserved arterial allografts: comparison with fresh and glutaraldehyde treated grafts

The use of cryopreserved aortic allografts in cardiovascular surgery is widespread and has resulted in excellent outcomes. However, it is controversial whether cryopreservation suppresses the antigenicity of tissue. We designed experimental models to study whether the cryopreservation process alters antigenicity in comparison with that found in fresh and glutaraldehyde treated tissues. Fresh, cryopreserved, and glutaraldehyde treated thoracic aorta from Brown Norway rats were subcutaneously implanted into Lewis rats. Inflammatory cells infiltrating around the grafts were measured on days 7, 14, 28, and 56 after implantation. The glutaraldehyde treated grafts showed significantly less infiltration than the fresh or cryopreserved grafts (p < 0.005). No significant difference was detected between the fresh and cryopreserved grafts. Another study examined the effect of modifications of the aortic allograft on subsequent allogeneic skin graft antigenicity. Subcutaneous implantation of fresh, cryopreserved, and glutaraldehyde treated aortic grafts from Brown Norway into Lewis rats resulted in subsequent skin graft rejection at 4.4+/-0.7, 5.1+/-0.8, and 6.6+/-2.1 days, respectively. There was no significant difference between the fresh and cryopreserved groups; whereas skin grafts in the glutaraldehyde group survived longer than those in the cryopreserved group. These results indicate that cryopreservation had no significant influence on antigenic suppression of arterial allografts.     

Arhinencephaly (holoprosencephaly) associated with external hydrocephaly

A female infant, weighing 2,263 g had been spontaneously delivered at the 33rd week of gestation. The only noticeable abnormality was a cleft palate, but within the next few days, she developed low temperature, spastic movements in the extremities, and depressed respiration. These abnormalities soon became worse and she died on the 12th day. Clinically, she was not suspected of having malformations of the brain, but on autopsy, an external hydrocephaly (400 ml) and small arhinencephalic brain (75 g) were noted. In the brain, the growth of the diencephalon was exceedingly poor but the growth of the rhombencephalon was relatively favorable. The olfactory bulbi and tracts in the telencephalon were absent. These findings were similar to those seen in cases of arhinencephaly (or holoprosencephaly). In the cerebral ventricles, the lateral ventricles and the IVth ventricle were enlarged, but the IIIrd ventricle could not be identified. Communication could only be found between the lateral apertures of the IVth ventricle and the subarachnoidal spaces.     

Determination of a splice acceptor site of pX gene in HTLV-I infected cells

The splice acceptor site of pX gene of HTLV-I has been determined to be at base position 7301 using S1 nuclease protection analysis. This splice acceptor site is used in all HTLV-I immortalized T-cell clones studied despite variation in the abundance levels of pX mRNA. Our results confirmed the proposal by Haseltine et al. (W. A. Haseltine, J. Sodroski, R. Patarca, D. Briggs, D. Perkins, and F. Wong-Staal, Science (Washington, D. C. 225, 421-424 (1984); K. Shimotono, W. Wachsman, Y. Takahashi, D. W. Golde, M. Miwa, T. Sigimura, and I. S. Y. Chen, Proc. Natl. Acad. Sci. USA 81, 6657-6661 (1984)) that a pX protein with a molecular weight of at least 38,000 could be synthesized. Generation of a 2.0-kb pX mRNA may involve a double-splicing event.     

Effects of sex hormones on induction of intestinal metaplasia by X-irradiation in rats.

The influence of sex hormones on induction of intestinal rnetaplasia was examined in 5 week old Crj: CD (SD) rats of both sexes. At the age of 4 weeks, the animals were gonadectornized and given testosterone or dimethyl estradiol (DES). One week after operation, they were irradiated with two 10 Gy doses of X-rays to the gastric region at a 3 day interval for a total of 20 Gy. At the termination of the experiment, 6 months after the X-irradiation, the incidence of intestinal metaplasia with alkaline phosphatase (ALP) positive foci in males was significantly higher than in females, in orchidectomized males or orchidectomized plus DES treated rats (P <0.01). On the other hand, the incidence of intestinal metaplasia with ALPpositive foci in normal females appeared lower than in ovariectomized females (P < 0.01), and was increased in rats by treatment with testosterone or decreased by DES. Numbers of foci of intestinal metaplasias with Paneth cells and total numbers appeared to increase in males treated with DES. The results suggested a promoting role for testosterone in the development of ALP positive lesions and indicated considerable heterogeneity between intestinal metaplasia subtypes.