Bone loss with increasing age induces osteoporosis. This loss may be due to increased bone resorption and decreased bone formation. Osteoporosis with a decrease in bone mass is widely recognized as a major public health problem. Pharmacological and nutritional factors may prevent bone loss with increasing age. The chemical compounds in food that act on bone metabolism, however, are poorly understood. Genistein is a natural isoflavonoid phytoestrogen found in Leguminosae and has been demonstrated to have an anabolic effect on bone metabolism, suggesting its role in the prevention of osteoporosis. Genistein has a stimulatory effect on bone formation and mineralization in the tissue culture system in vitro, and it can stimulate protein synthesis in osteoblastic cells. Moreover, genistein has been shown to inhibit osteoblastic bone resorption by preventing the formation and differentiation of osteoclast-like cells from bone marrow cells, and the apoptosis of mature osteoclasts is induced by genistein through the Ca2+ signaling mechanism. Also, the suppressive effect of genistein on rat bone osteoclasts is partly involved in the inhibition of protein kinase and the activation of protein tyrosine phosphatase in osteoclasts. Daidzein, an isoflavone, did not have a greater effect than genistein. Various polyphenols [glycitein, resveratol, quercetin, catechin, and (-)-epigallocatechin gallate] found in food and plants did not have an anabolic effect on bone calcification in tissue culture in vitro. Genistein may be of significance in the prevention of bone loss with increasing age. The dietary intake of isoflavone (genistein and daidzein) could prevent bone loss in ovariectomized rats which are model animals of osteoporosis. In addition, the preventive effect of genistein on bone loss with aging is enhanced by the combination of zinc or casein phosphopeptides as food factors. Genistein is a useful biofactor in the prevention of osteoporosis.
Chlorinated ethylenes (CEs) including tetrachloroethylene (PCE), trichloroethylene (TCE) and 1,1-dichloroethylene (DCE) were comparatively evaluated for their effects on the expression of cytochrome P450 (CYP) forms of subfamilies 1A, 2B, 2E and 3A as well as their relative suitability as substrates of these CYPs. The magnitudes of inhibition of the enzyme activities were as follows in descending order: 1,1-DCE > TCE > PCE against hepatic CYPs and PCE > 1,1-DCE > TCE against pulmonary CYP2B1. These organ-specific profiles in the sensitivities to the adverse effects of CEs were partly attributable to the differential expression patterns of CYP forms by which they were metabolically activated. The expression of hepatic and pulmonary CYP2B mRNA was severely suppressed in the presence of 1,1-DCE during the entire observation period until 30 hr after the CE-treatment, in marked contrast to the temporarily enhanced expression at 6 hr followed by a moderate suppression in the cases of PCE and TCE with the trough values being observed at 18 hr. In addition to CYP2B, 1,1-DCE in advance of the transcriptional stage, when simultaneously treated with phenobarbital, also exclusively suppressed CYP2E1. These general suppressive effects of 1,1-DCE on the expression of divergent CYP mRNAs in vivo resembled the published findings in primary cultured hepatocytes treated with inflammatory cytokines such as IL-1β, TNF-α and IL-6, implying the highly inflammatory nature of 1,1-DCE.
Iron-induced cytotoxicity in chronic hepatitis C was described in detail based on effectual iron reduction therapy. Without treatment, chronic hepatitis C may progress to cirrhosis and develop hepatocellular carcinoma. The first choice treatment for the disease is interferon. However, the cost-benefit of interferon treatments is so poor that options other than interferon are needed for poor responders. A minimum requirement for managing these patients is good control of disease activity shown by maintaining a low serum level of alanine aminotransferase activity. An index accepted widely is 80 IU/l or less of the enzyme activity. When patients were treated with repeated phlebotomy to remove body iron stores, the mean serum levels of enzyme activities changed from 128 to 63 IU/l. Maintaining patients at an iron deficient state for 5 years or more did not change the staging of liver histology, in contrast with the advanced liver histology in the control patients. Iron generates hydroxyl radicals that mediate peroxidation of membrane lipids. After the proposal of our empirical treatment based on the ultrastructural study of hepatic iron stores, evidence has been accumulated that oxidative stress via lipid peroxides plays an important role in the pathogenesis of chronic hepatitis C. The treatment is not yet authorized in Japan, but is approved in the United States as the first of the options to interferon. Considering the therapeutic effects of iron removal on both biochemical and histological parameters, the safety-proved economical procedure might be recommended for patients as an option to interferon.
The mutagenic characteristics of concentrates from environmental water such as the effluent from various treatment plants and river waters using a modified Blue Chitin column method were determined by Ames assay with Salmonella typhimurium TA98, YG1021 and YG1024. This was done to estimate the quantitative contribution rate of mutagenicity estimated from analyzed polycyclic aromatic hydrocarbons (PAHs) content in the same concentrates to the mutagenicity of environmental water. Moreover, PAHs content and the mutagenicity of the river sediment-extract were measured to elucidate the fate of PAHs in the river. Many kinds of environmental waters and river sediment possessed principally indirect frame-shift type mutagenicity. Concentrates from many kinds of environmental waters possibly contained aminoarenes assayed with YG1021 and YG1024. In many kinds of environmental waters, the contribution rates of mutagenic magnitude estimated from seventeen analyzed PAH contents to the mutagenic magnitude of these water concentrates in TA98 with S9 mix were recognized to be from 0.10 to 1.15%. However, the contribution rate of mutagenic magnitude estimated from ten analyzed PAHs contents to the mutagenic magnitude of the Arata River sediment extract in TA98 with S9 mix was 64.2%. The high concentration of PAHs in the river sediment suggested that hydrophobic PAHs in the water might easily accumulate in the river sediment after adsorbing to the suspended solid.
High concentrations of bisphenol A were detected in the effluent from several pulping processes for waste paper containing thermal paper and/or other printed paper. Chlorinated derivatives of bisphenol A were found to be formed by its reaction with a low concentration of chlorine in the effluent from the bleaching process using sodium hypochlorite. Poly-chlorinated derivatives were mainly detected in the final effluents from two plants because they were not biodegraded in the water recycling process by treatment with activated sludge. The estrogenic activities of bisphenol A and its chlorinated derivatives were evaluated by an agonist assay using the yeast two-hybrid system with and without a metabolic activation test using rat liver S9. All of the chlorinated derivatives tested showed more potent activity than bisphenol A without S9. The activity of 3,3′-dichlorinated BPA was 38-fold stronger than that of bisphenol A. The activities of these compounds were almost eliminated upon treatment with S9.
Vascular endothelial proteoglycans exhibit an antithrombogenic activity by activating antithrombin III and heparin cofactor II on the luminal surface of the vascular wall. Calcium spirulan (Ca-SP) is a novel sulfated polysaccharide isolated from the blue-green alga Spirulina platensis. Since Ca-SP exhibits antithrombin activity by activation of heparin cofactor II, we hypothesized that the polysaccharide may influence the metabolism of anticoagulant proteoglycans synthesized by endothelial cells. When cultured bovine aortic endothelial cells were treated with Ca-SP (50 μg/ml or less) in the presence of [35S]sulfate for 24 hr, the accumulation of labeled proteoglycans in the cell layer was decreased but that in the conditioned medium was significantly increased, indicating that Ca-SP inhibits the association of proteoglycans with vascular endothelial cell layers. Na-SP, which was prepared by replacement of calcium ion with sodium ion, showed an equal effect. When the endothelial cells were labeled with [35S]sulfate and then treated with Ca-SP (5 μg/ml or more) for 1 hr in the absence of [35S]sulfate, the percentage of [35S]sulfate-labeled proteoglycans released into the medium was markedly increased by Ca-SP. DEAE-Sephacel ion exchange chromatography of [35S]sulfate-labeled proteoglycans released into the medium from Na-SP-treated cells indicated that Na-SP stimulates the release of both heparan and chondroitin/dermatan sulfate proteoglycans from the cell layer. Taking these results together it is suggested that Ca-SP and Na-SP promote the release of proteoglycans from vascular endothelial cells by inhibiting the association of the macromolecules with the cell layer.
Five mutagenic and/or carcinogenic polynuclear aromatic hydrocarbons (PAHs), and Salmonella mutagenicity in airborne particles collected at three stations (industrial, commercial/residential, and agricultural areas) in Santiago, Chile were measured, and compared with the same measurements in the Tokyo metropolitan area. PAH concentrations showed daily variations in both cities. The concentrations of four-ring PAHs were higher in the Tokyo area than in Santiago, and the concentrations of five-or-more-ring PAHs were higher in Santiago than in the Tokyo area. Mutagenic activities also showed daily variations in both places, and were generally higher in Santiago. In the Tokyo area, the mutagenic activities were higher under conditions of TA98-S9 mix than under TA98+S9 mix while in Santiago, the activities were similar under the two mixes. There were good correlations between PAH concentrations and mutagenic activities in both areas. In Santiago, mutagenic activities and PAH concentrations were higher in the commercial/residential area and the industrial area than in the agricultural area.
A two- year retrospective study between 1996 and 1997 was carried out at the University of Nigeria Teaching Hospital, Enugu, to determine the patterns of intestinal helminth infection. A total of 13385 stool samples were examined using the direct smear technique. Some samples were also examined using the formal ether concentration method when direct smears were negative. Hookworm, Ascaris, Trichuris and Strongyloides were the most common helminths. Hookworm was the most prevalent (14.3%). Generally infection was most prevalent in adolescents aged 12-17 years, except for ascariasis, where the 6-11 year age group had the highest prevalence. Multiple infections were common (12.6%), with the most common combination being hookworm and ascariasis. To reduce the prevalence of various helminth infections the level of environmental sanitation, socioeconomic status of the populace and water supply should be improved.
We describe a novel approach to evaluating the respiratory toxicity of chemicals in the free-living nematode Caenorhabditis elegans. Using DOX-96KT, a general purpose, multi-channel dissolved oxygen (DO) measuring system, we measured the DO concentration in culture media containing C. elegans exposed to chemicals to assay for respiratory toxicity. The current value, which is an index of the dissolved oxygen concentration in culture media, was measured every 10 sec for 30 min at 24°C. We focused on the respiration levels of the exposed worms between 500 and 1800 sec. This method produces results that are similar to the computer tracking system measuring behavioral toxicity. Since it can do multiple dilution series tests at a given time, it is useful for concentration-activity correlation studies. This novel technique is not only an alternative to the computer tracking system for measuring behavioral toxicity but also a rapid sublethal toxicity test for chemical hazard assessment.
The antibacterial activity of the extracts prepared from 181 species (75 families) of tropical and subtropical plants was screened against various types of pathogenic bacteria. Among the 505 extracts tested, 53 of them inhibited the growth of methicillin-resistant Staphylococcus aureus (MRSA). The active extracts obtained from barks of Shorea hemsleyana and roots of Cyphostemma bainessi were separated to their components, some of which greatly reduced the viable cell number of MRSA. These active compounds were all identified as stilbene derivatives. Hemsleyanol d, one of the stilbene tetramer isolated from S. hemsleyana, was the most effective compound and had MIC of 2 μg/ml.
Human volunteers chewed polyvinyl chloride (PVC) products under controlled conditions for 60 min (four consecutive periods of 15 min), and then the amount of diisononyl phthalate (DINP) migration into the saliva was determined by HPLC. The PVC products consisted of a molded plate containing added DINP (500 mg/g) and five types of commercial toy containing 160-583 mg/g DINP (mean value 372 mg/g). The DINP migration rates ranged from 3.8 to 32.6 μg/cm2/hr (mean value 16.4 μg/cm2/hr). The DINP contents in the toy products did not correlate with the amount of in vivo migration. The DINP migration rates during the last 15-min period (45-60 min) decreased by 38-75% compared with the first session (0-15 min). In addition, in vitro DINP migration rates from the PVC products into saliva simulant during 15 min of rotary shaking were about 3.6-4.1-fold higher than the rates in vivo over 60 min, and remained essentially fixed for each sample.
Trehalose has been utilized as a supplement to various products such as food and cosmetics, and has recently been reported to have multiple biological functions in vitro and in vivo. We have previously found that trehalose administered orally inhibits mouse osteoclastogenesis induced by estrogen-deficiency or by injection of lipopolysaccharide (LPS). In this study, we examined whether oral administration of trehalose to mice produced changes in the Peyer's patches (PP) of the small intestine, that are essential for mucosal immune responses, to clarify the inhibitory mechanism of trehalose on osteoclastogenesis. Male C3H/HeN mice were orally administered trehalose 1 g/kg for 5 consecutive days. Interestingly, trehalose administration caused a significant decrease in the total number of PP lymphocytes (PPL) and in the spontaneous release of interleukin (IL)-6 by PPL compared with those of controls, without inducing apparent pathological damage. Moreover, proliferation and interferon (IFN)-γ production by PPL in response to LPS tended to increase compared with those of the control group. Considering that IL-6 and IFN-γ are factors associated with bone metabolism, our results suggest the possibility that trehalose ingestion may modify the intestinal immune environment, resulting in altered systemic immunity and bone metabolism.
Transmissible spongiform encephalopathy (TSE) is a neurodegenerative disease characterized by spongiform degeneration and accumulation of an infectious isoform (PrPSc) of the prion protein in the central nervous system. PrPSc originates from a ubiquitous cellular prion protein (PrPC). We attempted to develop an easy method of quantitative analysis of PrP by immunoblotting based on densitometry data for PrP bands in immunoblots. Both PrPC and PrPSc yield three bands in immunoblots, and they correspond to PrP molecules carrying two, one, and no Asn-linked sugar chains. We used bovine PrPC as a model protein in the immunoblotting study. We removed the Asn-linked sugar chains from the PrP molecules with N-glycanase to convert all three glycoforms of PrP into a single band of the deglycosylated form and determined the PrP by densitometry calibrated with recombinant bovine PrP.
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an endocrine disruptor that is known to have widespread effects on the reproductive system. We examined the effects of TCDD on testosterone production of primary cultured murine testicular cells. The cells, derived from the testes of ICR mice at age 65 days, were exposed to 10-2-104 pM TCDD for 3, 24, or 48 hr and treated with human chorionic gonadotropin for 6 hr to induce production of testosterone. At these concentrations of TCDD, the viability of testicular cells was not affected. No significant time- or TCDD concentration-dependent effects were observed on the secretion of testosterone. The data suggest that TCDD does not have a direct influence on testosterone production in the ICR mouse.
Some DNA topoisomerase inhibitors induce cleavage of DNA strands and lead to cell death. Therefore the inhibitors are utilized for chemotherapy against cancer. The treatment, however, can cause severe side effects such as genetic modification of normal cells. Camptothecin (CPT) and etoposide (VP16) belong to this class of anticancer agents that inhibit DNA topoisomerase I and II, respectively. In the present study, we investigated whether treatment with CPT and VP16 induces DNA breaks in nuclei reconstituted in Xenopus egg extract by observing focus formation of replication protein A (RPA), which is thought to accumulate on loci of DNA lesions prior to DNA repair. Treatment with CPT caused formation of discrete RPA foci at a later stage of incubation of demembranated Xenopus sperm nuclei with egg extracts. The RPA foci increased with the amount of CPT. However, at 30 min, before or just starting the initiation of DNA replication, the discrete RPA foci in CPT-containing extract were not obvious, suggesting that DNA replication is necessary for the focus formation induced by CPT. On the other hand, discrete RPA foci were induced by VP16 even at 30 min.
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