To investigate the safe handling of an industrial product, phenyl vinyl sulfone (PVS), which has an extremely high potential for dermal sensitization at low concentrations and positive mutagenicity, the maximum no-effect concentration for dermal deposits was obtained from dermal sensitization experiments. The systemic concentrations in the liver, which is considered to be a target tissue of mutation, were monitored using the TKTD (Toxico Kinetics Toxico Dynamics) model by inputting the maximum no-effect concentration of sensitization. The predicted highest concentration in the liver was compared with the no-effect level of mutation in the same tissue, which was derived from an in vitro mutagenicity study. The results showed that when this product is handled at lower concentrations, which may not induce dermal sensitization, the systemic concentrations would be lower than those causing mutation in the liver. In workplaces, conditions that prevent dermal sensitization caused by PVS could also protect against the mutagenicity of this compound.

Our objective was to evaluate the usefulness of cytomorphologic assessment in the accuracy of diagnosis of Hodgkin's disease (HD), using imprint cytological preparations over a 18-yr period. Imprint materials from 34 HD cases were reviewed using cytomorphological and immunocytochemical studies. Twenty-six cases (76.5%) were diagnosed to be HD and 6 cases (17.6%) were suspected to be HD, but 2 cases (5.9%) were cytologically diagnosed as reactive lesions, because of an insufficient number of Reed-Sternberg (RS) cells. The 6 suspected cases were definitively diagnosed as HD, using immunocytochemistry. Immunophenotyping of RS cells in 32 cases (excluding the two cases of reactive lesions) showed CD30+ in 31 (96.9%) cases, CD15+ in 22 (68.8%) cases and CD20+ in 12 (37.5%) cases. RS cells were immunophenotypically classified into five groups: A, (CD 30+, 15+, 20-) 15 (46.9%); B, (CD30+, 15-, 20-) 5 (15.6%); C, (CD 30+, 15+, 20+) 6 (18.8%); D, (CD30+, 15-, 20+) 5 (15.6%); and E, (CD30-, 15+, 20+) 1 (3.1%). Cytomorphologic differences in RS cells were identified between group D and other groups (CD15+ and/ or CD20-). The former had a low polymorphic shape (like popcorn), and the latter had a more classical polymorphic shape. Epstein-Barr virus (EBV)-latent membrane protein-1(LMP-1) was identified in 16 (50%) cases. LMP-1 expression was found not only in classic RS cells, but also in smaller variants. These variants did not match the morphologic criteria of RS cells, but expressed the common phenotype (CD30+, CD15+/-) of RS cells, suggesting the same cellular origin as RS cells. This study demonstrated that imprint cytology from lymph node biopsies can be a useful tool for the diagnosis and the evaluation of the cellular biology of HD.

The toxicokinetics/toxicodynamics (TKTD) model simulates the toxicokinetics of a chemical based on physiological data such as blood flow, tissue partition coefficients and metabolism. In this study, Andersen and Clewell's TKTD model was used with seven compartments and ten differential equations for calculating chemical balances in the compartments (Andersen and Clewell 1996, Workshop on physiologically-based pharmacokinetic/pharmacodynamic modeling and risk assessment, Aug. 5-16 at Colorado State University, U.S.A) . Using this model, the authors attempted to simulate the behavior of four chemicals: trichloroethylene, methylene chloride, styrene and n-hexane, and the results were evaluated. Simulations of the behavior of trichloroethylene taken in via inhalation and oral exposure routes were also done. The differences between simulations and measurements are due to the differences between the absorption rates of the exposure routes. By changing the absorption rates, the simulation showed agreement with the measured values. The simulations of the other three chemicals showed good results. Thus, this model is useful for simulating the behavior of chemicals for preliminary toxicity assessment.

BACKGROUNDHyaluronan (HA) synthesis is frequently observed in malignant mesothelioma cells, whereas it is rarely found in lymphoma cells. Previous studies have reported that a high HA concentration in the serum was related to poor prognosis in lymphomas, although the mechanism was not elucidated. We recently encountered a case of anaplastic large cell lymphoma with an HA-rich, massive, lymphomatous effusion. Several studies were performed to clarify the character of this unusual lymphoma and to observe whether the lymphoma cells synthesized HA.CASEA 59-year-old female was admitted with abdominal pain. Radiologic studies revealed a pleural effusion and paraaortic lymph node swelling. A biopsied specimen was compatible with anaplastic large cell lymphoma. Detailed cytologic observations revealed that the lymphoma cells in the pleural effusion had alcian blue-positive, productive material in the prominent Golgi area and microvillous structures on the surface. Further studies found that most of the lymphoma cells had HA-binding protein and expressed CD44 antigen, a receptor for HA. In addition, the HA concentration in the supernatant of the primary culture cells was extremely high and increased time dependently.CONCLUSIONThese observations suggest that the lymphoma cells synthesized and released HA. Interactions of the released HA and CD44 on the surface might play an important role in the peculiar serosal growth of lymphoma cells.

The sensitivities of three skin sensitization tests such as the Guinea pig maximization test (GPMT), Adjuvant and patch test (APT) and Buehler test (BT), were quantitatively compared with reference to induction and challenge concentrations. Four chemical which had different physico-chemical properties (octanol-water partition coefficient (logP) and reactivity with NH2-group) were used in order to clarify the effect of the physico-chemical properties of chemicals on the sensitivity of the different methods. The induction concentrations inducing a 50% positive response (IC50) demonstrated extreme variation with the three methods. For example, the BT/GPMT ratio of IC50 values for 2,4-dinitrochlorobenzene was 33, whereas that for maleic anhydride was 300,000. The results were thought to be caused by difference properties such as the logP and reactivity of chemicals. This correlation was confirmed by using 2-dodecen-1-yl succinic anhydride, which had the same reactivity but higher logP than that of maleic anhydride. On the other hand, the challenge concentrations inducing 50% positive responses (CC50) were less affected by the methods and the BT/GPMT ratios for CC50 values were all within a 10-fold range. These results suggest that the sensitivity might be strongly different with reference to induction concentration, but not challenge concentration among the three methods.

Quantitative structure–activity relationships (QSARs) for skin irritation potential were studied using twenty-four phenols. Based on the hypothesis that skin irritation is induced by reaction of phenols with macromolecules present in epidermal and dermal levels of the skin, the following descriptors for QSAR were selected, the absolute hardness (N) calculated from HOMO (the highest occupied molecular orbital) and LUMO (the lowest unoccupied molecular orbital) energy levels for reactivity, and logP (octanol–water partition coefficient) for permeability. Using these descriptors, we fitted a regression function to the set of skin irritation scores obtained from an in vivo study, which allowed derivation of equations (r=0.85). The equations were verified with six additional phenols, showing good correlations with the expected skin irritation scores. From the above findings, the equations can be considered useful for predicting the skin irritation potential of phenol compounds.

As part of a collaborative study, the Mammalian Mutagenesis Study Group (MMS), a sub-organization of the Environmental Mutagen Society of Japan (JEMS) conducted mutagenicity tests in MutaMouse. Using a positive selection method, we studied the organ-specificity and time dependence of mutation induction by 4-nitroquinoline 1-oxide (4NQO). A single dose of 4NQO was administered intraperitoneally (7.5 or 15 mg/kg) or orally (200 mg/kg) to groups of male mice. On days 7, 14 and 28 after treatment, we isolated the liver, kidney, lung, spleen, bone marrow, testis and stomach in the intraperitoneal administration experiment and the liver, lung, bone marrow, testis and stomach in the oral administration experiment. In addition, we performed the peripheral blood micronucleus test to evaluate clastogenicity. In the mice treated intraperitoneally at 7.5 mg/kg, we found increased mutant frequency (MF) only in the lung, where the MF did not vary with expression time. In the mice treated at 15 mg/kg, we found increased MF in the liver, bone marrow and lung. In orally treated mice, the MF was high in the lung and liver and very high in the bone marrow and stomach while the increase in the testis was negligible. As the expression time was prolonged, the MF tended to increase in the liver, decrease in the bone marrow, and remain stable in the lung, testis and stomach. The incidence of micronucleus induction in peripheral blood cells was significantly increased (p<0.01) in the 4NQO groups when compared with the vehicle control group by intraperitoneal treatment. Thus, these assay systems appeared to be of use in detecting not only genetic mutation but also chromosomal aberration.

Both male and female guinea pigs are widely used in tests to detect the skin-sensitizing potential of new chemicals. The aim of the present study was to investigate the influence of the animal gender on sensitization rates, with the guinea-pig maximization test (GPMT) using OECD recommended positive control sensitizers, and the differences of the density of Langerhans cells in male and female guinea pigs. The sensitization rates of males and females challenged with HCA, MBT or benzocaine gave almost the same results. There were no statistical differences between the mean responses of males and females. These results were confirmed by rechallenge with the OECD recommended positive controls. Furthermore, the density of Langerhans cells in abdominal epidermis in males (1229 +/- 45 cells/mm2) was the same as that in females (1242 +/- 89 cells/mm2). These results indicate that there is no significant influence of guinea-pig gender in the assessment of skin-sensitizing potential using the GPMT.

A cosmid shuttle vector containing the target gene of Escherichia coli gpt coding xanthine-guanine phosphoribosyl transferase was constructed. The shuttle vector was designed to be rescued into the gpt-deficient Escherichia coli from Chinese hamster CHL/IU cells through an in vitro packaging method. Mutations occurred at the target gene can be detected with a selective agent, 6-thioguanine (6-TG). The shuttle vector was stably transfected into CHL/IU cells to give several cell lines containing copies of the shuttle vector in the chromosomes. Each cell line exhibited a characteristic rescue efficiency (0 to 1.9 x 10(5) CFU/microgram of genomic DNA) of the shuttle vector and spontaneous mutation frequency (3.9 x 10(-5) to over 10(-2)) at the 6-TG selection. One transgenic cell line (KN63), which showed a higher rescue efficiency and a low spontaneous mutation frequency, was selected and tested for the ability to respond to a genotoxic agent, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). MNNG increased both the mutation frequency at the target gene and the number of the cells with chromosome aberrations. DNA sequence analysis of 6-TG mutants showed that predominant mutations (10/14) were identified as G:C to A:T transitions in MNNG-induced mutants, whereas transversions were predominant (5/9) in spontaneous mutants. These results suggest that this transgenic CHL/IU cell line can be a useful tool for analyzing the relation between gene mutations and chromosome aberrations.

We have evaluated a new semi-automated chromosome analysis system, employing the Magiscan human metaphase finder, for in vitro chromosomal aberration tests. The metaphases on a slide are recognized using the main system, a metaphase finder, and their stage coordinates are transferred to the satellite system, a computerized microscope with a motorized stage, by way of a diskette. In the satellite system, a researcher analyzes one metaphase after another at high power (100 x objective) without changing the objective. The effectiveness of the system, in comparison with the manual metaphase finding and analysis, was confirmed in in vitro chromosomal aberration tests using cultured Chinese hamster cells. Structural or numerical aberrations in the cells did not affect the metaphase findings. The system reduces the time for chromosome analysis by a factor of about 4. Moreover, the system provides perfect reproducibility for analyzing procedure. It is concluded that this semi-automated system is useful in in vitro chromosomal aberration tests.

The effect of fenitrothion on experimental allergic conjunctivitis was studied using guinea pigs. Guinea pigs were passively sensitized with anti-sera against ovalbumin (OVA) or Japanese cedar pollen. Eight days after the sensitization, 6 x 10(-5) mg/kg to 6 mg/kg of fenitrothion were administered subcutaneously. Two days after the injection, OVA or Japanese cedar pollen was given in the conjunctival sac and the allergic conjunctivitis was examined. OVA or Japanese cedar pollen induced the allergic conjunctivitis, depending on the challenge dosage (OVA). However, no adverse effect of fenitrothion was observed on allergic conjunctivitis challenged with OVA or Japanese cedar pollen. An anti-allergic agent, ketotifen, suppressed the allergic intensity. These results indicate that fenitrothion has no adverse effect on the experimental allergic conjunctivitis.

Predicting equations of subacute toxicity were developed by analyzing rat acute and subacute toxicity data of 56 chemicals of various structures. Minimum or 10% effect level in acute or subacute toxicity was estimated as a ''biological parameter''. Good regression equations were established between the geometrical means (''combined parameters'') of any two of the parameters of acute and subacute toxicities and introduction of log P to the equations improved the correlations with a statistically significant multiple regression coefficient. The lowest predicted effect level of the subacute toxicity, which is selected from the data calculated by the above several correlations, can predict the upper limit of the no observed effect level.