Hepatitis in skunks caused by the virus of infectious canine hepatitis.

Two cases of acute, fatal, hepatitis occurred in young, striped skunks (Mephitis mephitis) trapped in southern Ontario. Histologically, lesions in the liver were similar to infectious canine hepatitis. A virus was isolated which produced large intranuclear inclusions in dog kidney cell cultures. These inclusions were Feulgen-positive and fluoresced green with acridine orange stain. The skunk hepatitis isolate was identified as the virus of infectious canine hepatitis by virus neutralization tests.     

Effects of 5-fluorouracil on B lymphocyte lineage cells

The aim of these studies was to determine the sensitivity of B lymphocyte lineage precursor cells in mice to 5-fluorouracil (5-FU). Selective effects could be very helpful in dissecting precursor-product relationships between these and the rare multipotential stem cells from which they derive. Numbers and functions of particular types of cells were determined at intervals after a single treatment (3 mg) and, as expected, myeloid-committed stem cells were very severely affected. Day 8 spleen colony-forming cells (CFU-S) and colony-stimulating factor-responsive macrophage progenitors were reduced by 98% within 24 hr, whereas presumptive early stem cells (day 14 CFU-S) were much more resistant. B cells, which were probably recently formed in bone marrow and which are not thought to be actively dividing, were also 5-FU-sensitive, but perhaps less so than pre-B cells and immunoglobulin-negative lymphocytes bearing a B lineage marker. Approximately 5 wk were required for the normal cellular composition of marrow to return to normal. Transplantation of marrow from 5-FU-treated mice suggested that the slow regeneration of B lymphocytes might partially result from residual drug effects or damage to microenvironmental elements which are required for B lineage differentiation. Acute reductions of lymphocytes in the thymus were also documented, and the larger cells declined most rapidly and regenerated most slowly in that tissue. Of particular interest was the differential susceptibility of B cells in various lymphoid tissues to 5-FU. Whereas lymph node B cells were minimally affected, one-half of the splenic B cells disappeared within 48 hr of drug injection. Intrinsic differences in 5-FU sensitivity were confirmed by treatment of lymphocytes in vitro, and this suggests that particular B cell sets may be metabolically distinct. This drug should find additional experimental application in studies of B lymphocyte formation and functional heterogeneity.     

Booster effect of canine distemper, canine parvovirus infection and infectious canine hepatitis combination vaccine in domesticated adult dogs

Domesticated adult dogs with antibody titer classified as below 'high' to one or more of canine distemper virus (CDV), canine parvovirus type-2 (CPV-2) and canine adenovirus type-1 (CAdV-1) were then given an additional inoculation, and the effectiveness of this booster evaluated 2 months later. Consequently, CDV and CAdV-1 antibody titer experienced a significant increase, but the same effect was not observed in the antibody titer of CPV-2. These findings suggest that with additional inoculation, a booster effect may be expected in increasing antibody titers for CDV and CAdV-1, but it is unlikely to give an increase in CPV-2 antibody titer.     

重访乙型肝炎病毒感染肾脏的意义

乙型肝炎病毒(hepatitis B virus,HBV)嗜肝性主要由病毒与受体作用的特异性、支持共价闭合环状DNA(covalently closed circular DNA,cccDNA)形成的宿主因子和促进病毒RNA转录的核因子3种因素决定。人的肾脏很可能也提供这些要素,且许多研究发现HBV感染标记存在于慢性乙型肝炎患者的肾脏细胞中。本文探讨了HBV感染肾脏的可能性。由于目前血清乙型肝炎表面抗原(hepatitis B surface antigen,HBsAg)消失是功能性治愈慢性乙型肝炎的关键指标,如果肾脏也是HBV感染、表达和复制的另一靶器官,则肾脏在功能性治愈慢性乙型肝炎中的作用不可忽视。     

Effect of maternally derived antibody levels on antibody responses to canine parvovirus, canine distemper virus and infectious canine hepatitis virus after vaccinations in beagle puppies

Antibody titers against canine parvovirus (CPV), canine distemper virus (CDV) and infectious canine hepatitis virus (ICHV) in serum were measured in 6 beagle dams and their 38 puppies bred in our colony, in order to clarify the effects of maternally derived antibodies to antibody responses against the viruses after vaccinations in puppies. Correlation coefficient on antibody titers between puppies and dams were CPV: r = 0. 7935, CDV: r = 0.8194 and ICHV: r = 0.8105. Mean maternal antibody positive rates in 7-day-old puppies from their dams were CPV: 67%, CDV: 46% and ICHV: 45%. Mean half-lives of the maternal antibodies in puppies were estimated to be CPV: 13.5 days, CDV: 15.1 days and ICHV: 15.4 days. The antibody response against CPV vaccination in puppies was mainly observed in dogs being titers of less 1:5 and positivity was 39% (15/38 puppies) after 1st vaccination at 42 days after birth, and 82% (31/38 puppies) after 2nd vaccination at 70 days. That against CDV vaccination (at 56 days after birth) was seen highly in dogs being titers of less 1:10 and positivity was 53% (20/38). Also that against ICHV vaccination (at 56 days after birth) was seen frequently in dogs being titers of less 20 holds and the rate was 87% (33/38). From these results, it was estimated that the age when high antibody response against each vaccination could be expected in puppies might be CPV: between 40 and 69 days, CDV: between 32 and 92 days and ICHV: between 31 and 52 days, respectively.     

Effects of foscarnet on the cell kinetics of Madin-Darby canine kidney cells

The antiherpes compound, foscarnet (trisodium phosphonoformate), showed concentration-dependent effects on the cell kinetics of Madin-Darby canine kidney cells. At 1 mM, only minor effects could be seen on cell proliferation and cell cycle distribution, as measured by flow cytometry DNA analysis. Treatment with 5 mM foscarnet resulted in an accumulation of cells in the S-phase although no complete cell cycle block was evident. At 10 mM foscarnet, cells accumulated earlier in the S phase, probably at the G1/S border. However, at both 5 and 10 mM foscarnet the block was not established until after 15 h incubation. Upon removing 10 mM foscarnet after 24 h incubation, G1 cells rapidly entered the S phase, whereas the progression through S and G2 + M was delayed considerably. The DNA synthesizing S phase seems, therefore, to be the main cell cycle phase affected by foscarnet.