Effect of recent changes in atomic bomb survivor dosimetry on cancer mortality risk estimates

The Radiation Effects Research Foundation has recently implemented a new dosimetry system, DS02, to replace the previous system, DS86. This paper assesses the effect of the change on risk estimates for radiation-related solid cancer and leukemia mortality. The changes in dose estimates were smaller than many had anticipated, with the primary systematic change being an increase of about 10% in gamma-ray estimates for both cities. In particular, an anticipated large increase of the neutron component in Hiroshima for low-dose survivors did not materialize. However, DS02 improves on DS86 in many details, including the specifics of the radiation released by the bombs and the effects of shielding by structures and terrain. The data used here extend the last reported follow-up for solid cancers by 3 years, with a total of 10,085 deaths, and extends the follow-up for leukemia by 10 years, with a total of 296 deaths. For both solid cancer and leukemia, estimated age-time patterns and sex difference are virtually unchanged by the dosimetry revision. The estimates of solid-cancer radiation risk per sievert and the curvilinear dose response for leukemia are both decreased by about 8% by the dosimetry revision, due to the increase in the gamma-ray dose estimates. The apparent shape of the dose response is virtually unchanged by the dosimetry revision, but for solid cancers, the additional 3 years of follow-up has some effect. In particular, there is for the first time a statistically significant upward curvature for solid cancer on the restricted dose range 0-2 Sv. However, the low-dose slope of a linear-quadratic fit to that dose range should probably not be relied on for risk estimation, since that is substantially smaller than the linear slopes on ranges 0-1 Sv, 0-0.5 Sv, and 0- 0.25 Sv. Although it was anticipated that the new dosimetry system might reduce some apparent dose overestimates for Nagasaki factory workers, this did not materialize, and factory workers have significantly lower risk estimates. Whether or not one makes allowance for this, there is no statistically significant city difference in the estimated cancer risk.     

Effect of turpentine oil on C-reactive protein (CRP) production in rainbow trout (Oncorhynchus mykiss)

The effect of turpentine oil on C-reactive protein (CRP) production was studied in rainbow trout (Oncorhynchus mykiss). Serum CRP concentration was estimated by sandwich enzyme-linked immunosorbent assay using anti-rainbow trout CRP monoclonal antibody (mAb) AC4 and polyclonal antibody. Intracellular CRP was demonstrated by flow cytometry using anti-trout CRP mAb. Hepatocytes, head kidney macrophages, spleen lymphocytes and peripheral blood lymphocytes showed reaction against AC4, but RTG-2 fibroblastic line cells, derived from rainbow trout gonad did not. This is the first report on the detection of intracellular CRP in fish. CRP levels decreased significantly 1 day after intramuscular injection of turpentine oil and remained low for 14 days. Significant decreases in the expression of CRP in hepatocytes, head kidney macrophages and spleen lymphocytes after injection of turpentine oil were found. The reduction of serum CRP concentration after turpentine oil injection may be attributed to decreases in intracellular CRP synthesis.     

A novel adenovirus expressing human 4-1BB ligand enhances antitumor immunity

4-1BB ligand (4-1BBL), a member of the tumor necrosis factor (TNF) superfamily, interacts with 4-1BB (CDw137) expressed on activated T cells and delivers a costimulatory signal for T cell activation and growth. Various studies have demonstrated a role for murine 4-1BB in immune function, but relatively few investigations of human 4-1BB have been conducted. Here we report on the construction of a recombinant E1/E3-deleted adenovirus encoding human 4-1BBL (Ad4-1BBL) and its stimulation of antitumor immunity. Ad4-1BBL was able to efficiently infect several human adenocarcinoma cell lines and induce 4-1BBL expression on the cell surface within 24 h, this enhancing the antitumor activity not only of lymphokine-activated killer cells with a T cell phenotype (T-LAK) but also naive peripheral blood mononuclear cells (PBMC). This antitumor activity with T-LAK cells was further enhanced by addition of bispecific antibody (BsAb; anti-MUC1xanti-CD3). Cocultivation of Ad4-1BBL-infected tumor cells with either T-LAK cells or PBMC resulted in significant elevation of interferon-gamma (IFN-gamma), interleukin-2 (IL-2), and granulocyte-macrophage colony-stimulating factor (GM-CSF) production. Furthermore, remarkable tumor growth inhibition was observed in cholangiocarcinoma-grafted severe combined immunodeficient (SCID) mice to which Ad4-1BBL and T-LAK cells were administered when tumor size exceeded 5 mm in diameter. These results provide strong evidence in support of the efficacy of adenovirally delivered 4-1BBL for genetic immunotherapy of cancer.     

Recombinant bovine herpesvirus-1 expressing p23 protein of Cryptosporidium parvum induces neutralizing antibodies in rabbits

In order to develop a vaccine against cryptosporidiosis in cattle, we constructed a recombinant bovine herpesvirus-1 (BHV-1) expressing an immunodominant surface protein, p23, of Cryptosporidium parvum sporozoites. In the recombinant virus, the p23 gene under the control of a CAG promoter and a gene coding for an enhanced green fluorescent protein were integrated into the gG gene of BHV-1. Despite a low frequency of homologous recombination, cloning of the recombinants was easy because of the specific fluorescence of the plaques formed by recombinants. These plaques were among the plaques of the nonfluorescent parental virus. All clones selected for fluorescence also contained the p23 gene. In MDBK cells infected with the recombinant BHV-1, the antibody against the p23 protein recognized the p23 protein as an approximately 23-kDa specific band in Western blotting analysis. Rabbits immunized with the recombinant produced IgG against the p23 protein. It was also demonstrated that the sera of immunized rabbits reduced infection of C. parvum sporozoites in HCT-8 cells. The serum of an immunized rabbit reduced infection compared with the normal rabbit serum control. These results indicate that the recombinant BHV-1 induces neutralizing antibodies in rabbits.     

Characterization of hydrogen peroxide removal reaction by hemoglobin in the presence of reduced pyridine nucleotides

Hydrogen peroxide removal rates by hemoglobin were enhanced in the presence of reduced pyridine nucleotides. The species which had the activity to oxidize pyridine nucleotides was purified from human blood and identified as hemoglobin A. Hydrogen peroxide removal rates by hemoglobin A without reduced pyridine nucleotides at 0.2 mM hydrogen peroxide were 0.87+/-0.11 micromol/s/g hemoglobin, and the removal rates using 0.2 mM NADH and NADPH were 2.02+/-0.20 and 1.96+/-0.31 micromol/s/g hemoglobin, respectively. We deduced that the removal reaction by hemoglobin included formations of methemoglobin and the ferryl radical and reduction of the latter with pyridine nucleotides. The hydrogen peroxide removal ability by hemoglobin was less than that by catalase but was larger than that by glutathione peroxidase-glutathione reductase system at 0.2 mM hydrogen peroxide. Under acatalasemic conditions, it was suggested that NAD(P)H were important factors to prevent the oxidative degradation of hemoglobin.     

Foot formation in hydra: commitment of the basal disk cells in the lower peduncle

Foot regeneration in the freshwater hydra Pelmatohydra robusta was examined using a monoclonal antibody AE03 as a marker. This antibody specifically recognizes mucous-producing ectodermal epithelial cells in the basal disk, but not cells in the peduncle region located just above the basal disk in the foot. When the basal disk was removed by amputation at the upper or lower part of the peduncle, AE03-positive (basal disk) cells always appeared at the regenerating tip of the footless polyp approximately 12-16 h later. When a small piece of tissue was cut out from the upper or lower peduncle region, the tissue invariably turned into a smooth spherical or oblong shape within a few hours. AE03 signal appeared in these spheres variably depending on their origin: when tissue pieces were derived from the lower peduncle, the signal appeared in nearly all pieces and often covered the entire surface of the pieces within 24 h. In contrast, the signal appeared in less than 10% of pieces derived from the upper peduncle. Furthermore, the signal seldom covered more than half of the surface of these pieces. When maintained for many days, pieces derived from the upper peduncle often regenerated tentacles, whereas those from the lower peduncle seldom did. These and other observations suggest that epithelial cells in the peduncle can rapidly differentiate into basal disk cells when the basal tissue is removed. However, cells in the upper peduncle are not irreversibly committed to differentiate into basal disk cells because, when cut out as small tissue pieces, they could remain AE03 negative and become tentacle cells. In contrast, the cells in the lower peduncle apparently are irreversibly committed to differentiate into basal disk cells, as they always turned rapidly into AE03-positive cells once they were physically separated from (and freed from the influence of) the basal disk itself, regardless of the separation methods used.     

A new dipeptide,O-phosphoserylethanolamine isolated from Agkistroden blomhoffi (mamushi)

A new dipeptide was isolated from several tissues of Agkistroden blomhoffi (mamushi: a venomous snake in Japan), using ion-exchange resins and thin-layer chromatography. It was identified as O-phosphoserylethanolamine by mass spectrometry and comparison with synthetic compounds using several methods. This compound was contained in several mamushi tissues including the liver, heart, brain, bile, and muscle. The concentrations of O-phosphoserylethanolamine in the liver, brain, muscle, skin, heart, and bile were 7.17+/-3.11,16.98+/-4.25,37.37+/-7.88,37.56+/-8.97,23.93+/-6.11, and 22.21+/-5.76 micromol/g, respectively.     

T cells of atomic bomb survivors respond poorly to stimulation by Staphylococcus aureus toxins in vitro: does this stem from their peripheral lymphocyte populations having a diminished naïve CD4 T-cell content?

We found previously that the peripheral CD4 T-cell populations of heavily exposed A-bomb survivors contained fewer na?ve T cells than we detected in the corresponding unexposed controls. To determine whether this demonstrable impairment of the CD4 T-cell immunity of A-bomb survivors was likely to affect the responsiveness of their immune systems to infection by common pathogens, we tested the T cells of 723 survivors for their ability to proliferate in vitro after a challenge by each of the Staphylococcus aureus toxins SEB, SEC-2, SEC-3, SEE and TSST-1. The results presented here reveal that the proliferative responses of T cells of A-bomb survivors became progressively weaker as the radiation dose increased and did so in a manner that correlated well with the decreasing CD45RA-positive (na?ve) [but not CD45RA-negative (memory)] CD4 T-cell percentages that we found in their peripheral blood lymphocyte (PBL) populations. We also noted that the T cells of survivors with a history of myocardial infarction tended to respond poorly to several (or even all) of the S. aureus toxins, and that these same individuals had proportionally fewer CD45RA-positive (na?ve) CD4 T cells in their PBL populations than we detected in survivors with no myocardial infarction in their history. Taken together, these results clearly indicate that A-bomb irradiation led to an impairment of the ability of exposed individuals to maintain their na?ve T-cell pools. This may explain why A-bomb survivors tend to respond poorly to toxins encoded by the common pathogenic bacterium S. aureus.     

Diversity,abundance, and activity of archaeal populations in oil-contaminated groundwater accumulated at the bottom of an underground crude oil storage cavity

Fluorescence in situ hybridization has shown that cells labeled with an Archaea-specific probe (ARCH915) accounted for approximately 10% of the total cell count in oil-contaminated groundwater accumulated at the bottom of an underground crude oil storage cavity. Although chemical analyses have revealed vigorous consumption of nitrate in cavity groundwater, the present study found that the methane production rate was higher than the nitrate consumption rate. To characterize the likely archaeal populations responsible for methane production in this system, fragments of 16S ribosomal DNA (rDNA) were amplified by PCR using eight different combinations of universal and Archaea-specific primers. Sequence analysis of 324 clones produced 23 different archaeal sequence types, all of which were affiliated with the kingdom EURYARCHAEOTA: Among them, five sequence types (KuA1, KuA6, KuA12, KuA16, and KuA22) were obtained in abundance. KuA1 and KuA6 were closely related to the known methanogens Methanosaeta concilii (99% identical) and Methanomethylovorans hollandica (98%), respectively. Although no closely related organism was found for KuA12, it could be affiliated with the family METHANOMICROBIACEAE: KuA16 and KuA22 showed substantial homology only to some environmental clones. Both of these branched deeply in the Euryarchaeota, and may represent novel orders. Quantitative competitive PCR showed that KuA12 was the most abundant, accounting for approximately 50% of the total archaeal rDNA copies detected. KuA1 and KuA16 also constituted significant proportions of the total archaeal rDNA copies (7 and 17%, respectively). These results suggest that limited species of novel archaea were enriched in the oil storage cavity. An estimate of specific methane production rates suggests that they were active methanogens.