Induction of lung lesions by bronchial administration using bronchoscope technique in mice

This study aimed to establish an exposure method that can induce homogeneous lesions with minimal inter-individual variability. The distribution of lesions induced by bleomycin (BLM) administration was also analyzed. C57BL mice were intrabronchially administered 20 µL of BLM (3 mg/mL) using a bronchoscope in the left or right bronchus. The mice were sacrificed 14 days after administration, and their lungs were evaluated histopathologically. BLM-induced inflammatory lesions were widely observed in the lungs. In the left bronchus-treated group, lesions were uniformly observed throughout the lobe, and no individual differences were noted. Meanwhile, in the right bronchus-treated group, individual differences in the distribution of the pulmonary lesions were observed. The distribution of lesions differed among the four lobes of the right lung owing to their anatomical features. Administration into the left bronchus is recommended for highly homogeneous lung exposure and for establishing models that contribute to highly accurate toxicity and efficacy evaluations.

Transplantation of Chemical Compound-Induced Cells from Human Fibroblasts Improves Locomotor Recovery in a Spinal Cord Injury Rat Model

The development of regenerative medicine using cell therapy is eagerly awaited for diseases such as spinal cord injury (SCI), for which there has been no radical cure. We previously reported the direct conversion of human fibroblasts into neuronal-like cells using only chemical compounds; however, it is unclear whether chemical compound-induced neuronal-like (CiN) cells are clinically functional. In this study, we partially modified the method of inducing CiN cells (termed immature CiN cells) and examined their therapeutic efficacy, in a rat model of SCI, to investigate whether immature CiN cells are promising for clinical applications. Motor function recovery, after SCI, was assessed using the Basso, Beattie, and Bresnahan (BBB) test, as well as the CatWalk analysis. We found that locomotor recovery, after SCI in the immature CiN cell-transplanted group, was partially improved compared to that in the control group. Consistent with these results, magnetic resonance imaging (MRI) and histopathological analyses revealed that nerve recovery or preservation improved in the immature CiN cell-transplanted group. Furthermore, transcriptome analysis revealed that immature CiN cells highly express hepatocyte growth factor (HGF), which has recently been shown to be a promising therapeutic agent against SCI. Our findings suggest that immature CiN cells may provide an alternative strategy for the regenerative therapy of SCI.

Establishment and Validation of an Ultra-Short-Term Skin Carcinogenicity Bioassay Using Tg-rasH2 Mice

After initiation with 7,12-dimethylbenz[a]anthracene (DMBA), the promoting potential of 12-O-tetradecanoylphorbol-13-acetate (TPA) on skin tumor development can be detected by an ultra-short-term skin carcinogenicity bioassay using Tg-rasH2 mice. In the present study, 10 chemicals were assessed using this ultra-short-term bioassay as a first step to validate this practical and easy-to-use skin carcinogenicity bioassay. These chemicals belonged to 4 categories: dermal vehicles (acetone, 99.5% ethanol, anhydrous ethanol, and Vaseline), skin noncarcinogens (oleic acid diethanolamine condensate, benzethonium chloride, and diisopropylcarbodiimide), skin tumor promoters (TPA and benzoyl peroxide), and a skin carcinogen (4-vinyl-1-cyclohexene diepoxide). In a first study, DMBA was used as the initiator at a dose of 50 μg according to previous data, but skin tumors were observed in the no-treatment and vehicle groups. Therefore, the dose of DMBA for skin tumor initiation was reevaluated using 12.5 or 25 μg, with 12.5 μg found to be sufficient for initiation activity. In the ultra-short-term assay, the vehicles and skin noncarcinogens were negative while the skin tumor promoters and the skin carcinogen were positive. The detection of skin tumor promotion and carcinogenicity was feasible in only 8 weeks. In conclusion, this carcinogenicity bioassay may represent a useful tool for the assessment of the carcinogenicity potential of topically applied chemicals.

Influence of cerebral fluid drainage on the pharmacokinetics of vancomycin in neurosurgical patients

The objective of this study was to retrospectively investigate the influence of cerebral fluid drainage on the serum concentrations and pharmacokinetic parameters of vancomycin (VCM). We analyzed 55 patients with normal renal function who had been hospitalized in the neurosurgical ward and received intravenous infusions of VCM. We compared the daily doses of VCM, serum VCM concentrations, serum concentration/dose ratio (C/D ratio), and pharmacokinetic parameters calculated using the Sawchuk-Zaske method between patients who underwent cerebral fluid drainage (drainage group) and controls (non-drainage group). The patients in the drainage group showed a significantly lower trough concentration of VCM (5.8 ± 3.3 μg/mL) than that shown by the non-drainage group (9.9 ± 5.4 μg/mL, p = 0.017). Further, the patients in the drainage group showed a significantly lower trough C/D ratio (0.32 ± 0.17) than that shown by the non-drainage group (0.50 ± 0.31, p = 0.047). In conclusion, cerebral fluid drainage may influence VCM pharmacokinetics. Our findings strongly suggest that a high dose of VCM is required to maintain optimal serum concentrations of VCM in patients managed with cerebral fluid drainage.

Biocompatibility of cross-linked hyaluronate (Gel-200) for the treatment of knee osteoarthritis

OBJECTIVE

To compare the biocompatibility and immunogenicity of two intra-articular hyaluronan formulations, Gel-200 (Gel-One(®)) and hylan G-F 20 (Synvisc(®) series).

EXPERIMENTAL DESIGN

A comparison of the biocompatibility of Gel-200 and hylan G-F 20 was made using a rat subcutaneous air pouch model and the knee joint of normal rabbits. Immunogenicity was evaluated using a homologous passive cutaneous anaphylaxis (PCA) assay in guinea pigs.

RESULTS

In the air pouch model in rats, characteristic fibrous belts formed in the subcutaneous tissue. Injection of hylan G-F 20 into the air pouch induced granulomatous nodules primarily composed of macrophages, multinucleated giant cells, and eosinophils accompanied with the test material in the center of the nodules in the fibrous belt. Furthermore, the thickness of the fibrous belt in the hylan G-F 20 group increased significantly compared to the saline group. Injection of Gel-200 into the air pouch induced neither granulomatous inflammation nor significant thickening of fibrous belt, while foamy macrophages containing the test material were observed. Intra-articular injection of hylan G-F 20 into the rabbit knee joints induced granulomatous inflammation, eosinophil infiltration, and significant increase in the number of cells in the synovial fluid, while these findings were absent in the Gel-200 group. In the immunogenicity assay, hylan G-F 20 induced a positive PCA reaction, but the Gel-200 did not.

CONCLUSION

Gel-200 showed more favorable biocompatibility and less immunogenicity compared to hylan G-F 20. Gel-200 is expected to be a single injection hyaluronan product with less safety concerns for the treatment of knee osteoarthritis (OA) pain.

Tumor Promotion by 12-O-Tetradecanoylphorbol-13-Acetate in an Ultra-Short-Term Skin Carcinogenesis Bioassay Using rasH2 Mice

Assessment of the skin tumor–promoting potential of 12- O-tetradecanoylphorbol-13-acetate (TPA) after initiation with 7,12-dimethylbenz[ a]anthracene (DMBA) was conducted using rasH2 transgenic (Tg) mice and their nontransgenic (non-Tg) littermates. Mice were treated with DMBA (50 μg/100 μL acetone) on clipped back skin at the commencement of the study, and 1 week thereafter, TPA was applied at 8 μg/200 μL or 4 μg/200 μL acetone, once or twice weekly, for 7 weeks. Skin nodules were observed in the rasH2 Tg mice from week 4, and the incidence reached 100% at weeks 5 and 6. The number of skin nodules (multiplicity) in the 8-μg twice-weekly, 8-μg once-weekly, 4-μg twice-weekly, and 4-μg once-weekly groups was 62.4, 46.2, 62.6, and 36.9, respectively. The non-Tg mice also developed skin nodules, but the sensitivity to induction in the rasH2 Tg mice was higher. No nodules were observed in the acetone groups, but single nodules were apparent in the no-treatment rasH2 Tg and non-Tg groups. In conclusion, skin promotion effects could be detected within only 8 weeks in the rasH2 mice, and the concentration of 4 μg TPA once weekly was sufficient as a positive control. This short-term skin carcinogenesis bioassay using rasH2 mice could represent a useful tool for the assessment of drug and chemical safety with cutaneous treatment.

Establishing a Laboratory Animal Model From a Transgenic Animal

Transgenic animal models have been used in small numbers in gene function studies in vivo for a period of time, but more recently, the use of a single transgenic animal model has been approved as a second species, 6-month alternative (to the routine 2-year, 2-animal model) used in short-term carcinogenicity studies for generating regulatory application data of new drugs. This article addresses many of the issues associated with the creation and use of one of these transgenic models, the rasH2 mouse, for regulatory science. The discussion includes strategies for mass producing mice with the same stable phenotype, including constructing the transgene, choosing a founder mouse, and controlling both the transgene and background genes; strategies for developing the model for regulatory science, including measurements of carcinogen susceptibility, stability of a large-scale production system, and monitoring for uniform carcinogenicity responses; and finally, efficient use of the transgenic animal model on study. Approximately 20% of mouse carcinogenicity studies for new drug applications in the United States currently use transgenic models, typically the rasH2 mouse. The rasH2 mouse could contribute to animal welfare by reducing the numbers of animals used as well as reducing the cost of carcinogenicity studies. A better understanding of the advantages and disadvantages of the transgenic rasH2 mouse will result in greater and more efficient use of this animal model in the future.

Detection of the onset of ischemia and carcinogenesis by hypoxia-inducible transcription factor-based in vivo bioluminescence imaging

An animal model for the early detection of common fatal diseases such as ischemic diseases and cancer is desirable for the development of new drugs and treatment strategies. Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that regulates oxygen homeostasis and plays key roles in a number of diseases, including cancer. Here, we established transgenic (Tg) mice that carry HRE/ODD-luciferase (HOL) gene, which generates bioluminescence in an HIF-1-dependent manner and was successfully used in this study to monitor HIF-1 activity in ischemic tissues. To monitor carcinogenesis in vivo, we mated HOL mice with rasH2 Tg mice, which are highly sensitive to carcinogens and are used for short-term carcinogenicity assessments. After rasH2-HOL Tg mice were treated with N-methyl-N-nitrosourea, bioluminescence was detected noninvasively as early as 9 weeks in tissues that contained papillomas and malignant lesions. These results suggest that the Tg mouse lines we established hold significant potential for monitoring the early onset of both ischemia and carcinogenesis and that these lines will be useful for screening chemicals for carcinogenic potential.

Use of IC tags in short-term carcinogenicity study on CB6F1 TGrasH2 mice

We studied the effect of IC tags, subcutaneously implanted animal identification tools, on rasH2 mice. A 26-week short-term carcinogenicity study was performed on a total of 299 mice including 75 male and female rasH2 mice each, and 74 male and 75 female non-Tg mice from the same litter as the rasH2 mice divided into a non-IC tag group, the IC-tag group, acetone group, TPA group and MNU group (all of the animals except for those in the non-IC tag group) had IC tags implanted subcutaneously in their backs. The administration methods of the positive control drugs TPA (2.5 micro g/kg, 3 times/week, percutaneously) and MNU (75 mg/kg, single intraperitoneal injection) were based on the protocol of the ILSI/HESI international collaborative study. The results showed no differences in the tumorigenic incidence and organs developing tumors between the IC tag and non-IC tag groups in both rasH2 and non-Tg mice. In the positive control MNU group, the tumorigenic incidence and organs developing tumors were the same as the background data and no promotion of carcinogenesis was observed. In all IC tag groups including the TPA group and MNU group, a fibrous capsule was formed around the IC tags subcutaneously, but no inflammatory changes or neoplastic changes were observed. From these findings, it was concluded that the IC tag has no effect on a 26-week carcinogenicity test of rasH2 mice under the conditions of the present study.

A larval medaka (Oryzias latipes) acute toxicity assay combined with solid-phase extraction to efficiently determine the toxicity of organic contaminants in river water

Using a larval medaka (Oryzias latipes) acute toxicity assay combined with solid-phase extraction, we proposed a method for efficiently determining the fish toxicity of organic contaminants in river water. Organic toxicants were 10, 20, 50 and 100-fold concentrated from 4 L of the sample with adsorption cartridges. The lethal effect was observed by exposing every ten individuals of 48-72 h old larval medaka to 20 mL of each solution for 48h. The median lethal concentration rate (LCR50) was used as an indicator for the toxicity. With the developed toxicity test method, more than seven times difference was found in the LCR50 of the river water samples. LCR50 distribution profiles were compared with 125 samples in two typical rivers. The result revealed a lower toxicity level in the mainstream than in the confluences, and a lower toxicity level in Sagami River than in Ayase River. LCR50 proved unique as a toxicity indicator, which was impossible to speculate from the conventional water quality indicator of the dissolved organic carbon concentration. As an effective screening test for priority settings, the method can help us with an efficient planning for the environmental investigation and management.

Development of a novel solid phase extraction method for the analysis of bacterial quinones in activated sludge with a higher reliability

A novel analytical method for analysis of microbial quinones in activated sludge sample was developed with improved reliability compared to the conventional method. The operating conditions for the extraction of quinones from activated sludge sample with a methanol-chloroform mixture and hexane were optimized. A solid phase extraction method using the Sep-Pak Plus Silica, a small column packed with silica gel, was employed for the purification and separation of quinones instead of column chromatography and thin layer column chromatography used in the conventional method. The analytical operation was simplified and the analytical time was shortened by a half or two-thirds of that required for the conventional method. The recoveries of quinones were markedly increased from 30-60% with the conventional method to as high as 90-101% with the improved method, demonstrating that the reliability of the analytical results of the improved method is significantly higher than that of the conventional method. The quinone content value obtained using the improved method was twice as high as that obtained using the conventional method for the same activated sludge sample, but the quinone profiles expressed as the mole fraction of each quinone type were the same for each method.

Histologic study of the regeneration process of human hair follicles grafted onto SCID mice after bulb amputation

This study examines histologically the degeneration and subsequent regeneration processes of human hair follicles whose bulb is severely damaged. Human scalp hair follicles were isolated and grafted onto immunodeficient mice after their bulb was amputated. On day 14, thickening and corrugation of the vitreous membrane, apoptosis of follicular keratinocytes, and regression of the lower portion of the follicles were observed. By day 20, mesenchymal cells had accumulated around the lower end of the follicles. From day 14 through 50, the follicular regression and apoptosis continued, and between days 30 and 40 the follicles became maximally shortened, and the vitreous membrane disappeared. By day 50 the lower end of the follicles had become cup-shaped, and the cup surrounded an aggregate of mesenchymal cells that corresponded to the dermal papilla. By day 60, all the grafted follicles had developed into anagen VI follicles, and the apoptosis had ceased. These results indicate that human scalp hair follicles whose bulb is completely destroyed enter into dystrophic telogen after restoration of the dermal papilla, then into anagen, and that the duration of the dystrophic telogen is shorter than that of the normal hair cycle.

Convenient dioxin measuring method using an efficient sampling train, an efficient HPLC system and a highly sensitive HRGC/LRMS with a PTV injector

An efficient sampling method for dioxins from flue gas, an efficient automatic purification and fractionation method by a new HPLC system using a sulfuric acid-silica/silica column, a Nitro column and a PGC column, and sensitive determination method by an economical HRGC/LRMS using a programmable temperature vaporization (PTV) injector were developed. It was confirmed that the dioxins could be easily collected by the proposed simple sampling train consisting of only two bottles, and the extracted sample could be purified sufficiently and separated as mono-ortho PCBs, non-ortho PCBs and PCDDs/PCDFs completely with the proposed HPLC system. The peak areas of GC/MS were increased linearly with the injection volume up to 40 microl by the PTV technique, and the sensitivity could be increased to 20 times higher than usual. This convenient measuring method can drastically reduce operation time, consumption of hazardous solvent and cost.

Method for measuring mutagen formation potential (MFP) on chlorination as a new water quality index

A novel water quality index, the mutagen formation potential (MFP) is proposed for use in evaluation of the quality of drinking water which may contain pollutants capable of forming mutagens when chlorinated under the conditions used in water purification processes. A method for measuring MFP was established as follows. The water sample to be tested is diluted until the TOC reaches 3-4 mg l-1, the pH is adjusted to 7.0 +/- 0.2, sodium hypochlorite is added to obtain conditions where Cl/TOC = 3-4 mg Cl (mg C)-1, and the water sample is left standing for 24 +/- 2 h at room temperature. Thereafter, 21 of the chlorinated water sample at pH 2.0 +/- 0.1 is passed through a Sep-Pak Plus CSP-800 cartridge to adsorb any mutagens formed, and DMSO is applied to the cartridge to desorb the mutagens. Then, a 2 ml sample of the eluate is collected after the DMSO had begun to flow out of the cartridge and evaluated by the Ames Salmonella mutagenicity assay (preincubation method).

Tsutsugamushi disease in Kanagawa Prefecture, Japan: clinical report of two cases and survey of other incidences in 1998

Tsutsugamushi disease is characterized by the early appearance of a black crust at the bitten area and the subsequent development of macular or macropapular rush on the whole body with high fever. While treatment with tetracycline derivatives and chloramphenicols is effective, delayed diagnosis or inappropriate treatment will lead to fatality. In this report, we describe two typical cases of tsutsugamushi disease and discuss other incidences in Kanagawa Prefecture, Japan, in 1998. One of the present two patients was diagnosed to be a case of the new type by Kawasaki strain of Rickettsia tsutsugamushi, while responsible strain was not identified for the other case. Since the disease is spreading widely even to suburban areas, we emphasize the need to consider the possible diagnosis of tsutsugamushi disease in patients with generalized eruption and high fever.

Overexpression of human H-ras transgene is responsible for tumors induced by chemical carcinogens in mice

Level of human prototype H-ras transgene expression in tumors induced by chemical carcinogens (N-ethyl-N-nitrosourea and N-methyl-N-nitrosourea) was analyzed in human H-ras transgenic mice (CB6F1-TgrasH2 Jic mice). All forestomach tumors examined revealed about 2-fold overexpression of the human H-ras transgene with or without point mutation at codon 12 or codon 61. However, endogenous mouse H- and K-ras genes exhibited neither point mutation nor overexpression. These results suggested that increased levels of ras gene products in the cell played an important role in facilitating chemical carcinogenesis in transgenic mice.

A measuring method of chlorobenzenes as a convenient substitute index of dioxins in stack gas from waste incineration facilities

Much labor, high technical skill and extreme cost are required to measure dioxins for obtaining the toxic equivalent quantity (TEQ) values. On one side, it was found that there were high amounts of chlorobenzenes (CBZs) in the flue gas from waste incineration facilities, and they are also thought to be one of the principal precursors for dioxins. The concentrations of CBZs could be used as a convenient substitute index to the TEQ values for controlling and monitoring dioxins in stack gas from waste incineration facilities as shown in another report. In this study, collection efficiencies in the sampling performed by a convenient train which was composed of two bottles containing water and diethylene glycol in a cooling box, recoveries in the evaporation of the extract by an evaporator, proper procedure of the concentration by nitrogen purge were investigated for measuring CBZs. It was found that tetra-, penta-, and hexa-chlorobenzenes (Cl4-6BZs) whose boiling points are higher than ca. 240 degrees C could be sufficiently collected and recovered in the sampling and the evaporation. For sufficient recoveries of Cl4-6BZs in the concentration by the nitrogen purge, the final volume should be larger than 200 microliters with a proper receiver of the K-D concentrator at 35 degrees C. However, Cl1-3BZs were lost in each of the procedures.

Induction of drug metabolism-related enzymes by methylcholanthrene and phenobarbital in transgenic mice carrying human prototype c-Ha-ras gene and their wild type littermates

Transgenic mice hemizygously carrying human c-Ha-ras proto-oncogene, Tg-rasH2 show very sensitive and facilitated carcinogenicity to various carcinogens. In this study, activities of certain enzymes related to drug metabolism and energy metabolism were measured in microsome and cytosol fractions of livers of Tg-rasH2 mice and their wild type littermates with both sexes treated with 3-methylcholanthrene (MC) and phenobarbital (PB). Aminopyrine N-demethylase activities increased significantly in livers of all mice treated with PB. MC and PB treatments induced significant increases in activities of UDP-glucuronosyltransferase and S-adenosyl homocysteinase compared to those in the non-treated groups in microsome fractions from all mice. In cytosol fractions of livers of all mice, glutathione S-transferase activity was significantly induced in the PB treated groups. There were no significant differences in activities of lactate dehydrogenase, glucose 6-phosphate dehydrogenase, pyruvate kinase and glucose 6-phosphatase related to energy metabolism in livers and kidneys among all mice. Tg-rasH2 mice showed stable activities of enzymes related to drug detoxication and energy metabolism similar to those of non-transgenic mice. These results suggest that the human c-Ha-ras transgene may not affect drug metabolism-related enzymes, and the facilitated carcinogenic response in the Tg-rasH2 mouse is not due to these enzymatic disorders.

Convenient substitute indices to toxic equivalent quantity for controlling and monitoring dioxins in stack gas from waste incineration facilities

It is necessary to develop technical systems for controlling and monitoring dioxins in stack gas from waste incineration facilities. However, it required much labor, high technical skill and extreme cost to measure dioxins for obtaining the toxic equivalent quantity (TEQ) values. In this study, the positive correlations of the WHO-TEQ values of PCDDs/PCDFs/Co-PCBs or PCDDs/PCDFs with the conventional I-TEQ values of PCDDs/PCDFs were confirmed beforehand for a large number of incineration facilities in a wide concentration range of a hundred thousand times. The relationships between the TEQ values and the concentrations of total PCDDs/PCDFs, each toxic isomer of PCDDs/PCDFs, total Cl4-6BZs, or each homologue of Cl4-6BZs were investigated for various incineration facilities. And it was found that positive correlations of the TEQ values with the concentrations of total PCDDs/PCDFs, 2,3,4,7,8-P5CDF, or Cl5BZ for a large number of different incineration facilities and in a wide concentration range. Consequently, the concentrations of total PCDDs/PCDFs, 2,3,4,7,8-P5CDF and Cl5BZ, whose measuring methods are much easier than that of obtaining the TEQ values, could be used as convenient substitute indices to the TEQ values for controlling and monitoring dioxins in stack gas from various waste incineration facilities.

Adsorption equilibriums of principal herbicides on paddy soils in Japan

Herbicides used in paddy fields during the flooding season can easily cause pollution by run-off into rivers or by other routes. It is very important to know the adsorption characteristics that influence their fate in the soil. The adsorption equilibriums have often been expressed by Henry equations, and the values of equilibrium constant, Kd, are estimated from the adsorption constants, K(OC), based on organic carbon contents of soils. There is little information concerning the equilibrium values expressed by the Freundlich equations, and insufficient information on the actual concentration levels in the paddy field. Therefore, adsorption equilibriums of the five principal herbicides: esprocarb, mefenacet, pretilachlor, simetryn and thiobencarb, on five kinds of paddy soil in Japan were investigated. It was found that their equilibrium values were better expressed by the Freundlich equation for concentration levels for the paddy fields, and that the values for the adsorption coefficient, n, varied from 1.0 to 1.6. Values for the coefficient, k, were in the range of 29-420 mg(1 - 1/n) l(1/n)/kg-dry, and the values were poorly related to solubilities in water or to the octanol-water partition coefficients of the herbicides. For each herbicide, except for simetryn, the values of k among the soils differed by 2-3 times, and no correlation could be found with the organic carbon contents, specific surface areas, pH, cation exchange capacity or major minerals of the soils. The adsorption equilibriums calculated from the values of adsorption constant Kd by the values of K(OC) in the literature were found to be very different from the experimental equilibriums. From the experimental values of coefficient k and n of the Freundlich equation, the maximum runoff concentrations of the herbicides were preliminarily estimated by a simple equilibrium model.

Histologic and cell kinetic studies of hair loss and subsequent recovery process of human scalp hair follicles grafted onto severe combined immunodeficient mice

To establish a model for studying human scalp hair, individually isolated hair follicles were grafted onto back skin of severe combined immunodeficient mice. Histologic changes and cell kinetics in the hair loss and subsequent recovery process were investigated. In the dystrophic stage (from day 7 to 30), all the hair shafts became dystrophic and were shed. Thickening and corrugation of vitreous membrane, apoptosis, and regression of the lower part were observed in the grafted hair follicles. 5-bromo-2'-deoxy-uridine-labeled cells were not detected in the lower end of the follicles, and keratin 19-positive cells appeared there. At the end of this stage their lower part was maximally retracted, secondary germ remained beneath the bulge, and the vitreous membrane disappeared. In the regeneration stage (from day 30 to 50), the same histologic findings as those at the end of the dystrophic stage were observed. The keratin 19-positive cells in the secondary germ, however, were replaced with keratin 19-negative and 5-bromo-2'-deoxy-uridine-labeled cells. Then, differentiation into an inner root sheath and a hair shaft began, and apoptosis was terminated. In the stable growth stage (from day 40 to at least 150), the grafted follicles were immunohistochemically and light microscopically identical with the normal anagen hair follicles except for the presence of melanin incontinence. These findings suggest that the grafted hair follicles entered into dystrophic catagen, subsequently dystrophic telogen, then returned to normal anagen follicles, and that stem cells or their close progeny in the secondary germ play an important part in the recovery process.

Decontamination of human xenotransplantable tumor with mouse hepatitis virus by implantation in nude rat: a case report

A human tumor xenograft contaminated with mouse hepatitis virus (MHV) was implanted in a nude rat in order to decontaminate the tumor line. The decontamination failed in the first trial, but succeeded in the second trial. The difference between the two trials was the duration of implantation of the tumor in the nude rat, i.e., 12 days in the first and 24 days in the second trial. Duration of implantation might be a factor in the decontamination of transplantable tumors infected with MHV by passaging in the nude rat.

The quantitative and qualitative defect of CD4+ CD45RO+ memory-type T cells are involved in the abnormality of TH1 immunity in atopic dermatitis patients

Peripheral blood mononuclear cells (PBMCs) obtained from atopic dermatitis (AD) patients produced low levels of IFN-gamma in response to Dermatophagoides farinae antigen (Der f Ag) plus IL-2 or OKT3 MoAb in contrast with PBMCs obtained from healthy donors. The reduced IFN-gamma production in AD patients' T cells appeared to be derived from the defect of CD4+ T cells but not CD8+ T cells. Indeed, from the cytoplasmic staining analysis of cytokines, it was demonstrated that the frequency of IFN-gamma producing CD4+ T cells (TH1 cells) in AD patients was markedly lower than that of healthy donors. From the phenotypic analysis using flow cytometry, it was also found that the number of CD4+ CD45RO+ memory type T cells was significantly reduced in AD patients compared with that of healthy donors. In addition to quantitative defect of memory type CD4+ T cells, functional defect of CD4+ CD45RO+ memory type T cells was also demonstrated in AD patients. Enriched CD4+ CD45RO+ T cells obtained from AD patients, who exhibited greatly reduced delayed-type hypersensitivity (DTH) response in tuberculin test, showed no significant TH1 immunity in terms of IFN-gamma production by stimulation with OKT3 MoAb or purified protein derivative (PPD). Thus, the immunological abnormality of TH1 immunity in AD patients appeared to be induced in concomitant with both the quantitative and qualitative defect of memory type CD4+ T cells.

Validation of transgenic mice harboring the human prototype c-Ha-ras gene as a bioassay model for rapid carcinogenicity testing

Studies were conducted to validate the transgenic (Tg) mice harboring human prototype c-Ha-ras gene, namely the rasH2 mice (CB6F1), as a model for rapid carcinogenicity testing. Short-term (26 weeks) carcinogenicity testing of 18 mutagenic (Salmonella) trans-species carcinogens, two mutagenic single-species (mouse-only) carcinogens, six non-mutagenic trans-species carcinogens, one non-mutagenic single-species (mouse-only) carcinogen, four mutagenic non-carcinogens and four non-mutagenic non-carcinogens were completed. The studies revealed that the Tg mice are able to detect various types of mutagenic carcinogens and may also detect various non-mutagenic carcinogens within 26 weeks. Dose-dependent tumor responses were observed with various carcinogens except for a few equivocal cases. The validation studies also revealed that the Tg mice are generally much more susceptible to both mutagenic and non-mutagenic carcinogens than control non-Tg mice. Most of the malignant tumors were observed in the carcinogen-treated Tg mice and only very few or none in the corresponding non-Tg mice. Most of the carcinogens tested induced some of the target organ tumors observed in B6C3F1 mice in a 2-year bioassay as well as certain types of tumors specific to the Tg mice, i.e. lung alveolar epithelial tumors, spleen hemangiosarcomas, forestomach squamous cell tumors. No significant tumor induction has been observed in the Tg mice either with mutagenic or non-mutagenic non-carcinogens. Although further validation studies are still required, the rasH2 mouse seems to be a promising candidate as an animal model for the development of a rapid carcinogenicity testing system.

Statistical procedures for estimating the detection limit and determination limit of the Ames Salmonella mutagenicity assay

Novel and flexible procedures for estimating the detection limit as well as the determination limit of the Ames mutagenicity assay were proposed to evaluate the genetoxicity of a water sample. The accumulated data under the test conditions of TA 100-S9 by our group were taken as examples and analyzed to estimate the detection limit and the determination limit. The detection limit was estimated at 1.7 as the MR value when duplicate plates were used in the negative control test. However, it decreased to 1.4 as the MR level when quadruple plates were used in the negative control test. Therefore it was found that the sensitivity of the Ames mutagenicity assay was improved very easily by increasing the number of plates for the negative control test from two to four. The application of the conventional twofold rule to the data obtained with the strain TA100 was considered too conservative. The determination limit was regarded at 2.2 as the MR value under the following conditions: (a) quadruple plates were used in the negative control test; (b) three dose-steps including negative control step were designed at regular intervals; and (c) duplicate plates were used for each dose-step. It was proved by comparing data of two students that the detection limit and the determination limit estimated in this study were considered acceptable to any well trained students.

Mutagenic activities of exhaust gas and ash from sludge incineration plants

We have found that the exhaust gas from many incineration plants of municipal solid wastes (MSW) show significant mutagenic activities. The mutagenic activities of exhaust gas from incineration plants of the other wastes have not been studied in detail. Here, we analyzed the mutagenic activities and compounds in exhaust gas and ash from seven sludge incineration plants. Some samples of the exhaust gas from the sludge incineration plants showed high mutagenic activities; although, none of the ash residues showed mutagenic activities. There was no relationship between the mutagenic activities and furnace types, the plant size or the apparent residence time of the gas in the furnace. The mutagenic activities of the exhaust gas were produced during incomplete combustion at lower temperatures. Direct mutagenic activities without S9 mix were higher than indirect mutagenic activities with S9 mix which was made from rat liver homogenate and was used to test mutagenic activity after metabolism. These results are different to those of MSW incineration plants. We analyzed the mutagenic compounds in the exhaust gas by GC/MS after fractionation by HPLC, but they could not be identified. We found that the mutagenic compounds in the exhaust gas were different from the compounds that were produced from the MSW incineration plants. We believed that these mutagenic compounds might be non-volatile and more polar than the heterocyclic amines, Trp-P-2, Trp-P-1 and Glu-P-1, which are typical mutagenic compounds in sewage and sludge.

Validation of transgenic mice carrying the human prototype c-Ha-ras gene as a bioassay model for rapid carcinogenicity testing

Carcinogenicity testing is indispensable for identifying environmental carcinogens and for evaluating the safety of drugs in the process of development. Conventional 2-year rodent bioassays are one of the most resource-consuming tests in terms of animals, time, and costs. Development of rapid carcinogenicity testing systems that can assess carcinogenicity within a short period has become a social demand and is essential to improve efficacy in the identification of environmental carcinogens as well as in the development of new drugs. In this review we introduce the rapid carcinogenicity testing system using transgenic (Tg) mice carrying the human prototype c-Ha-ras gene, namely rasH2 mouse (CB6F1-TgHras2 mouse is the same mouse). The studies have been conducted to validate the rasH2 mouse as a model for the rapid carcinogenicity testing system. Our current validation studies revealed that rasH2 mice are able to detect various types of mutagenic carcinogens within 6 months. The rasH2 mice may also be able to detect various nonmutagenic carcinogens. The validation studies also revealed that rasH2 mice are generally much more susceptible to both mutagenic and nonmutagenic carcinogens than control non-Tg mice. No significant tumor induction has been observed in rasH2 mice with either mutagenic or nonmutagenic noncarcinogens. More rapid onset and higher incidence of more malignant tumors can be expected with a high probability after treatment with various carcinogens in the rasH2 mice than in control non-Tg mice. The rasH2 mouse appears to be a promising candidate as an animal model for development of a rapid carcinogenicity testing system.

Kinetic characterization of binding and internalization of fractionated [3H]heparin in rat liver parenchymal cells in primary culture

The binding and internalization of fractionated [3H]heparin (FH) was kinetically analyzed in rat liver parenchymal cells to clarify its cellular uptake mechanism. The binding of FH to the cell surface was saturable with the dissociation constant (Kd) of 53.5 nM and a maximum binding capacity (Bmax) of 19.9 pmol/mg protein. The binding of FH to the cell surface was competitively inhibited not only by heparan sulfate, a polyanion analogous to heparin, but also by rose bengal, an organic anion, suggesting the binding is based on an electric interaction requiring an anionic charge for substrates and consistent with the earlier suggestion of the involvement of the scavenger-like receptor. According to kinetic model analysis, the rate constants of association (K(on)), dissociation (k(off)), and internalization (k(int).app) were estimated to be 0.0005 nM-1 min-1, 0.0112 min-1, and 0.0056 min-1, respectively. Although both Kd and Bmax were larger than those reported in Kupffer cells, suggesting lower affinity and higher capacity in liver parenchymal cells, the apparent internalization rate constant was similar to that in Kupffer cells. We thus provided additional evidence suggesting that a scavenger-like receptor exists in rat liver parenchymal cells, and then kinetically characterized the surface binding and internalization of fractionated heparin by this receptor.

PUVA treatment of human keratinocytes suppresses the surface expression of intercellular adhesion molecule 1 (ICAM-1) and inhibits adherence of PHA-blasts in vitro

To determine the basis of the therapeutic efficacy of Psoralens and UVA (PUVA) in inflammatory skin diseases, the effect of PUVA on the expression of cell adhesion molecules of keratinocytes was investigated in vitro. The addition of IFN-gamma and TNF-alpha to human keratinocytes in culture up-regulated the expression of ICAM-1 and HLA-DR on the cell surface. The cultured human keratinocytes were exposed to UVA light in the presence of 8-methoxypsoralen (PUVA). The ICAM-1 and HLA-DR surface molecules were stained by monoclonal antibodies, and the intensity of the resultant fluorescence was analyzed by FACS-can. PUVA treatment suppressed the expression of these cell surface molecules, with increasing UVA fluence. Moreover, PHA-blasts failed to adhere to PUVA treated keratinocytes. When keratinocytes were treated with PUVA prior to the addition of IFN-gamma and TNF-alpha, ICAM-1 and HLA-DR expression was suppressed. These results suggest that one of the therapeutic mechanisms of PUVA in inflammatory skin diseases is by inhibition of the adhesion of activated lymphocytes to keratinocytes due to suppression of cell surface molecules. It also suggests that PUVA may be useful as maintenance therapy for inflammatory skin diseases.

New immunodeficient (nude-scid, beige-scid) mice as excellent recipients of human skin grafts containing intraepidermal neoplasms

Engraftment of normal or lesional human skin onto nude or SCID (severe combined immunodeficiency) mice has been used as an in vivo experimental model. However, this model has some limitations, such as shrinkage and loss of the grafted skin over time. To improve the experimental model, we have produced two new SCID-lineage mouse strains, BALB/cA-nude-scid (nu/nu, scid/scid) and BALB/cA-beige-scid (bg/bg, scid/scid) mice, by the method of cross intercross. Intraepidermal neoplastic lesions such as Bowen's disease were grafted onto the back of the mice of these strains. The rate of reduction in the size of the grafts was lower on nude-scid and beige-scid mice than on SCID mice. Rates of survival of neoplastic cells in the grafts were higher in nude-scid mice than in SCID and beige-scid mice (SCID mice 38%, nude-scid mice 55%, beige-scid mice 38%). Neoplastic cells of Bowen's disease grafted onto a beige-scid mouse proliferated and invaded the dermis during 233 days of observation, confirming the progression to invasive squamous cell carcinoma from carcinoma in situ. The present study revealed that nude-scid and beige-scide mice newly produced by us provide a very useful in vivo experimental model for the investigation of carcinogenesis and tumor progression in human skin.

Molecular weight dependency in the uptake of fractionated [3H]heparin in isolated rat Kupffer cells

The uptake of low molecular weight fractionated [3H]heparin (LMWFH, 10000 Da) was compared with that of high molecular weight fractionated [3H]heparin (HMWFH, 23000 Da) in isolated rat Kupffer cells. Several heparin analogs, including HMWFH and ligands of scavenger receptors, inhibited both the surface binding and internalization of LMWFH, suggesting the involvement of scavenger receptors in the uptake of LMWFH in isolated rat Kupffer cells as well as HMWFH, in spite of a large difference in molecular weight. Metabolic inhibitors (2,4-dinitrophenol and rotenone), receptor-mediated and adsorptive endocytosis of polypeptides (phenylarsine oxide) and phagocytosis inhibitors (cytochalasine B and colchicine) did not inhibit the internalization of LMWFH. These results suggest that the scavenger receptor-mediated uptake of LMWFH is ATP-independent and different from receptor-mediated and adsorptive endocytosis of polypeptides and phagocytosis, in agreement with our previous results for HMWFH. The equilibrium binding of LMWFH to Kupffer cells was concentration-dependent with the dissociation constant (Kd) of 50 nM and maximum binding capacity (Bmax) of 2.3 pmol/10(6) cells. The dissociation constant of LMWFH was an order of magnitude larger than that of HMWFH (5.7 nM), suggesting a decrease in binding affinity to scavenger receptors with a decrease in the molecular weight of fractionated heparin. It was also shown that LMWFH is internalized by scavenger receptors according to first-order kinetics with an apparent internalization rate constant (Kint,app) of 0.0053 min-1, which is about half that for HMWFH (0.0118 min-1). Molecular weight thus appears to be one of dominant factors determining the uptake of fractionated heparin by scavenger receptors in Kupffer cells, and may partly explain the reported lower hepatic uptake of low molecular weight heparin than that of unfractionated heparin.

Uptake mechanism of fractioned [(3)H]heparin in isolated rat kupffer cells: involvement of scavenger receptors

The uptake of fractionated [(3)H]heparin was examined to elucidate the uptake mechanism in isolated rat Kupffer cells. The equilibrium binding of fractionated [(3)H]heparin to Kupffer cells was concentration-dependent with the dissociation constant of 5.7 nM and the maximum binding capacity of 1.5 pmol/10(6) cells. Several ligands of scavenger receptors inhibited the binding of fractionated [(3)H]heparin to Kupffer cells competitively and also the internalization of heparin, suggesting the involvement of scavenger receptors in the uptake of fractionated [(3)H]heparin. Fractionated [(3)H]heparin was also suggested to be internalized according to first order kinetics with the apparent internalization rate constant of 0.010 min (-1). Lowering temperature from 37 to 4 degrees C reduced the fraction internalized from 33% to 6% without affecting the total association, while the fraction internalized at 25 degrees C was comparable with that at 37 degrees C. Metabolic inhibitors (2,4-dinitrophenol and rotenone), an inhibitor of receptor-mediated and adsorptive endocytosis of polypeptides (phenylarsine oxide) and phagocytosis inhibitors (cytochalasine B and colchicine) did not inhibit the internalization of fractionated [3(H)]heparin. As known inhibitors of receptor-mediated and adsorptive endocytosis of polypeptides and phagocytosis did not affect the uptake of fractionated heparin, the scavenger receptor-mediated uptake is suggested to be ATP-independent and different from receptor-mediated and adsorptive endocytosis of polypeptides and phagocytosis, although for temperature dependency it showed the typical characteristics of receptor-mediated endocytosis.

Characteristics of lethal substances and the removal effect of molecular sulfur in the Salmonella mutagenicity test for river sediments

The lethal action and the effect from the removal of molecular sulfur by copper treatment were investigated in the Salmonella mutagenicity test for river sediments. Survival ratios of Ames Salmonella strains for five different sediment extracts were tested, and it was found that many of the river sediments showed the lethal action on TA98 and TA100, and the lethal action was stronger in the sample from which larger amount of extracts per unit weight were obtained. It was also found that the lethal action was reduced with the addition of the metabolizer S9 mix, and TA98 was more resistant than TA100 against the lethal substances in sediment extracts. Further, removal of molecular sulfur, one of the lethal substances, by copper treatment raised survival ratios of the tester strains. On high-pressure liquid chromatographic fractionation, the lethal substances, including molecular sulfur distributed in non-polar and slightly polar fractions, and medium or high polar fractions did not reveal lethal action. Consequently, the removal procedure of molecular sulfur was proper for applying on the fraction contained non-polar and slightly polar compounds.

A new approach to analysis of human sweating

In human skin transplanted to the back of 3 strains of immuno-deficient mice the function of the eccrine sweat glands of the human transplant was tested by topical intradermal application of pilocarpine, adrenaline and atropine + pilocarpine. Sweat responses were observed in pre-selected fields of observation by means of video macroscope. The iodine starch reaction served as an indicator for the appearance of sweat sport and permitted the evaluation of areas wetted by sweat in the field of observation. Among 9 animals tested, the hybrids between the CB-17-scid mouse and the BALB/cA-nu mouse (BALB/cA-nu,scid) seemed to exhibit the most consistent sweating response to local pharmacological stimulation. According to histological examination, eccrine sweat glands were preserved in human skin transplanted into the back skin of the BALB/cA-nu,scid mouse strain. The heterologous, human skin graft provides a novel model permitting, independent of the normal sweat gland innervation, the analysis of molecular receptors of sweat gland cells by which the actions of natural transmitters and pharmacological agents are transduced.

Macromolecule-macromolecule interaction in drug distribution. IV. Molecular weight dependency in the interaction of fractionated [3H]heparin with plasma proteins

Molecular weight dependency in the interaction of fractionated [3H]heparin (FH) with plasma proteins was evaluated by determining the protein binding of low molecular weight fractionated [3H]heparin (LMWFH: 7000 Da) and high molecular weight fractionated [3H]heparin (HMWFH: 16000 Da) by ultrafiltration and the effects of plasma proteins on the uptake in rat hepatocytes in primary culture. The unbound fractions of LMWFH were 0.5 and 0.8 in the presence of alpha-globulin and albumin, respectively, and were about 10 times larger than those of HMWFH, 0.04 and 0.1, suggesting a reduction in binding with a decrease in molecular weight. However, while the uptake of LMWFH was reduced by these proteins by the extents similar to bound fractions of LMWFH, the uptake of HMWFH was reduced by extents far smaller than bound fractions and comparable with those for LMWFH. Thus, it seemed that, while only unbound LMWFH is available for uptake, HMWFH bound to proteins is to some extent available for uptake (protein-mediated transport). The protein-mediated transport of heparin seemed to reduce with a decrease in molecular weight. It was also shown that the extended uptake of LMWFH was smaller than that of HMWFH not only in the absence of proteins but also in the presence of alpha-globulin, the major binding protein. The lower uptake of LMWFH is consistent with in vivo suggestion of lower hepatic accumulation.

Failure of genotoxic carcinogens to produce tumors in human skin xenografts transplanted to SCID mice

Chemical carcinogenesis of human skin was investigated using human skin xenografts (16 full thickness and 48 split thickness skin grafts) transplanted to CB-17-scid (SCID) mice. Topical application of a carcinogen, i.e. 7,12-dimethylbenz[a]anthracene (DMBA), benzo[a]pyrene, methylcholanthrene or N-methyl-N'-nitro-N-nitrosoguanidine, to the human skin xenografts once a week for 25-30 weeks failed to produce skin tumors. Both DMBA application plus UV-B irradiation and alternate applications of the above four carcinogens in combination with UV-B irradiation also failed to produce tumors. All of these treatments induced skin papillomas in skins of host SCID mice. DMBA induced skin papillomas in allogenic CD-1 mouse skin grafts transplanted to SCID mice. These results indicate that susceptibility of human skin to these carcinogenic stimuli is much lower than that of mouse skin.

Testing and classification methods for the biodegradabilities of organic compounds under anaerobic conditions

Biodegradability is one of the most important characteristics of an organic compound for predicting its fate and life in the environment and its application in biological wastewater treatment. But there is no general testing method for biodegradability under anaerobic conditions. The biodegradabilities of thirteen principal organic compounds was investigated in a batch test using vials under various conditions, such as the concentration of an organic compound, the cultivation method and the concentration of anaerobic bacteria for seeding. Two test methods in the standard concentration and the low concentration were developed. A new method to classify the biodegradabilities of organic compounds into thirteen ranks was proposed by considering inhibition, complete biodegradation and first step biodegradation.

Biodegradation ranks of priority organic compounds under anaerobic conditions

The biodegradations of 52 priority organic compounds were evaluated under anaerobic conditions by two tests developed in a preceding paper (Urano et al., 1995). Namely, the biodegradabilities of the compounds were classified into 13 ranks by the method proposed by Urano et al. (1995). Most of the aliphatic alcohols and carboxylic acids were not inhibitory and were biodegraded, but the compounds having ether bonds or branched hydrocarbon groups were biodegraded slowly. Aliphatic aldehyde and amines were not so much inhibitory but were hardly biodegraded. The benzene substitutes having groups of -CH2OH, -CHO, -CH2CH(NH2)COOH, -COOH and -OH were easily biodegraded, but the compounds having groups of -NO2, -NH2 and -SO3H were hardly biodegraded. Most of the nitro compounds were inhibitory in the higher concentration test though they were reduced into amino compounds. Since the biodegradation characteristics of many organic compounds could be classified and discussed appropriately, the suitability of the proposed method is substantiated.