Construction and expression of vectors encoding biologically active rodent gonadotropins

The gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), are important hormones in vertebrate reproduction. The isolation of gonadotropins from the pituitary gland is sub-optimal, as the cross-contamination of one hormone with another is common and often results in the variation in the measured activity of LH and FSH. The production of recombinant hormones is, therefore, a viable approach to solve this problem. This study aimed to express recombinant rat, mouse, and mastomys FSH and LH in Chinese hamster ovary (CHO) cells. Their common α-subunits along with their hormone-specific β-subunits were encoded in a single mammalian expression vector. FSH from all three species was expressed, whereas expression was achieved only for the mouse LH. Immunohistochemistry for rat alpha subunit of glycoprotein hormone (αGSU) and LHβ and FSHβ subunits confirmed the production of the dimeric hormone in CHO cells. The recombinant rodent gonadotropins were confirmed to be biologically active; estradiol production was increased by recombinant FSH in granulosa cells, while recombinant LH increased testosterone production in Leydig cells.

Tumorigenesis inheritance from the putative progenitor species of Nicotiana rustica

Hybrid seedlings from crosses of Nicotiana rustica×N. langsdorffii and N. rustica×N. alata show tumors including teratomas and vitrification. In the present study, we attempted to elucidate the genetic background leading to tumorigenesis and vitrification from the viewpoint of the amphidiploidy of N. rustica. The species N. undulata, N. paniculata, and N. knightiana have been suggested to be the progenitors of N. rustica or closely related to its progenitors. We tested tumorigenesis in interspecific hybrids between these putative progenitors of N. rustica and N. langsdorffii or N. alata, which are the species in section Alatae. The hybrid seedlings were cultured in test tubes and their morphological characteristics were observed. According to previous reports, most of the hybrid seedlings from the crosses N. rustica×N. langsdorffii and N. rustica×N. alata formed tumors and showed vitrification. In crosses with every putative progenitor of N. rustica, a portion of hybrid seedlings formed tumors and showed vitrification. These observations suggested that N. rustica inherited the factors leading to expression of abnormal symptoms from its putative progenitors. We also observed the influence of high temperature on the expression of abnormal symptoms of hybrid seedlings from the cross N. rustica×N. alata. While these hybrids developed teratomas and other tumors at 28°C, when cultured at 34°C, they did not show any abnormalities. This is the first report to show that phenotypic abnormalities in hybrid seedlings of N. rustica×N. alata are temperature sensitive.

Effects of bisphosphonates on human esophageal squamous cell carcinoma cell survival

Esophageal squamous cell carcinoma (ESCC) is one of the most malignant cancers in Japan. Anticancer chemotherapy has been useful for ESCC treatment. However, therapeutic options are limited. Recently, bisphosphonates (BPs), which are osteoporosis drugs, have shown anticancer effects in several cancer cell lines, but the effects against ESCC cell lines are unknown. In this study, we examined the cytotoxic effects of BPs and their mechanisms of cytotoxicity in human ESCC cell lines. A first-generation BP (etidronate), two second-generation BPs (alendronate and pamidronate), and two third-generation BPs (risedronate and zoledronate) were used in this study. All BPs, except etidronate, were cytotoxic, as indicated by increased caspase-3/7 activity and numbers of Annexin-fluorescein isothiocyanate positive cells in ESCC cell lines. From cell cycle analysis, G0/G1-phase arrest was observed upon treatment with second- and third-generation BPs. In addition, Cyclin D1 protein expression levels were decreased by second- and third-generation BP treatment. Although squalene and trans, trans-farnesol minimally affected BP cytotoxicity, treatment with geranylgeraniol inhibited BP cytotoxicity almost completely. We concluded that second- and third-generation BPs are cytotoxic to ESCC cell lines as they induce apoptosis and inhibit the cell cycle through mevalonate pathway inhibition. Therefore, BP treatment may be a beneficial therapy in ESCC patients.

Sex differences in spatiotemporal expression of AR, ERα, and ERβ mRNA in the perinatal mouse brain

It has been shown that every masculinized function might be organized by a particular contribution of androgens vs. estrogens in a critical time window. Here, we aimed to investigate the sex differences in brain testosterone levels and in the spatiotemporal dynamics of steroid receptor mRNA expression in perinatal mice, by using enzyme immunoassay and real-time PCR, respectively. We found that testosterone levels in the forebrain transiently increased around birth in male mice. During the perinatal period, levels of androgen receptor mRNA in the hypothalamus (hypo) and prefrontal cortex (PFC) were higher in male mice than in female mice. Estrogen receptor α (ERα) mRNA levels in the hypo and hippocampus were higher in male mice than in female mice before birth. In contrast, ERβ mRNA expression in the PFC was higher in female mice immediately after birth. These spatiotemporal sex differences in steroid receptor expression might contribute to organizing sex differences of not only reproductive function, but also anxiety, stress responses, and cognition in mice.

Chlorination by-products of fenitrothion

The mutagens produced through chemical reaction between chlorine and the insecticide fenitrothion were studied by using a quadrupole GC-MS. The mutagenicity and the mutagen formation potential (MFP) of the identified by-products were evaluated by the Ames assay (preincubation method) using Salmonella typhimurium TA100 without exogenous activation by S9 mix (TA100-S9). Before conducting GC/MS analyses, six compounds were presumed to be produced in chlorinated fenitrothion. These compounds were confirmed to be produced by the GC/MS analyses, but none of them were mutagenic. One of the chlorination by-products, 3-methyl-4-nitrophenol, has 19 times greater MFP than that of fenitrothion. This result suggests that a major mutagen in chlorinated fenitrothion will be produced via a chemical reaction between chlorine and 3-methyl-4-nitrophenol.

Mitemcinal (GM-611), an orally active motilin agonist, facilitates defecation in rabbits and dogs without causing loose stools

The effects of mitemcinal (GM-611), an orally active motilin agonist, on defecation were investigated in rabbits and dogs. In normal rabbits, within 0-3 h of dosing, orally administered mitemcinal (2.5-10 mg kg(-1)) increased stool weight in a dose-dependent manner without causing loose stools. Sennoside (12-48 mg kg(-1)) also facilitated defecation within 2-9 h of oral administration, but the stools were significantly loosened. In the morphine-induced constipation model, the stool weight of morphine-treated rabbits (1 mg kg(-1)) was only 37.5% of that of untreated animals. Mitemcinal (0.5-20 mg kg(-1)) dose-dependently increased stool weight without increasing stool water content. At the highest dose of mitemcinal, stool weight recovered to 83.9% of that of untreated animals. In normal dogs, mitemcinal (0.3-3 mg kg(-1)) reduced the time to first bowel movement after oral administration without inducing diarrhoea at any dose. These results indicate that mitemcinal facilitates defecation without inducing severe diarrhoea. It is suggested that mitemcinal may be a novel therapeutic agent for constipation that enables easier control of the timing of defecation because of the early onset and short duration of its action, compared with sennoside.

Mitemcinal (GM-611), an orally active motilin receptor agonist, accelerates colonic motility and bowel movement in conscious dogs

The prokinetic effects of mitemcinal, an orally active motilin receptor agonist, on the lower gastrointestinal tracts were investigated in conscious dogs. Oral administration of mitemcinal (0.1-1 mg/kg) stimulated colonic motility, which was measured by chronically implanted force-transducers, as well as gastric motility in a dose-dependent manner. The gastrointestinal contractile activities induced by mitemcinal were inhibited by the continuous intravenous infusion of GM-109, a selective motilin receptor antagonist. Oral administration of mitemcinal (0.3-3 mg/kg) also accelerated bowel movement after feeding without inducing diarrhea in dogs. The results demonstrate that mitemcinal stimulates colonic motility via motilin receptors and the effect of mitemcinal on colonic motility may reflect bowel movement after feeding. Thus, mitemcinal could be a promising agent for treatment of not only the upper but also the lower gastrointestinal motility disorders.

Arsenic removal from groundwater by a newly developed adsorbent

A novel adsorbent, which had been developed for phosphate adsorption, was adopted for arsenic removal from groundwater. Adsorption isotherm, pH dependence of the isotherm and adsorption rate were studied by batch method. Furthermore, by using a granular adsorbent of 1.8 mm diameter which is commercially available, lab-scale experiments of continuous adsorption treatment of actual groundwater containing arsenic at 50 mg m(-3) were conducted to examine the performance of the adsorbent. A large amount of arsenic, i.e., 10 g As kg(-1), was adsorbed at pH 7.0 and 10 mg As m(-3) in equilibrium concentration. It was only a 5% higher amount compared to conventional activated alumina. However, twice the bed volume, i.e., total volume of effluent divided by empty column volume, was achieved till breakthrough by using this novel adsorbent. This may be because the pH decrease, which enlarges apparent adsorption capacity of the adsorbent, is caused by a self-pH decrease function of the adsorbent. The self-pH decrease function must be delivered by dissociation of Al (III) aquoion. The proton release was clearly observed in batch experiments.

Denitrification of industrial wastewater with sulfur and limestone packed column

An autotrophic denitrification system was developed for nitrate contaminated industrial wastewater whose C/N ratio was very low. The microbes containing Thiobacillus denitrificans as a dominant species were attached on the surface of granular elemental sulfur packed in a column. Elemental sulfur was used as an electron donor for autotrophic denitrification. The granules of limestone were mixed with the granular sulfur to moderate the decrease of alkalinity during autotrophic denitrification. The stoichiometry and basic kinetics of denitrification were studied in column runs. The effects of minerals such as phosphorus on treatment performance were clarified. The wastewater from steel production plants was treated by the present biofilm process. Low extent of nitrogen removal was caused by the lack of minerals.

Removal of mutagen precursor from wastewater by activated sludge and oxidation treatment

Removal of mutagen precursors from wastewaters was investigated. Removal extent of mutagen precursor was evaluated by the mutagen formation potential (MFP) which is mutagenicity of pollutants capable of forming mutagens when chlorinated under the conditions of water purification processes. 77% of the MFP reduction extent for a wastewater from a university was achieved by activated sludge treatment. However, no significant reduction of the MFP was observed for wastewater from food industry, a landfill leachate and mold extract. The Fenton oxidation treatment and ozone treatment are able to remove mutagen precursors from the mold extract and the wastewater from a university, respectively. 90% of the MFP reduction extent was achieved for the mold extract by the Fenton treatment. 54% of the MFP reduction extent was achieved for a sewage by the ozone treatment. Using the oxidation treatments, biodegradability of mutagen precursors in the mold extract and sewage was improved. From the viewpoint of treatment cost, the oxidation treatments should be oriented to the improvement of biodegradability.

[Intraperitoneal cisplatin chemotherapy for ovarian cancer]

It is well known that the 5-year survival rate of advanced ovarian cancer patients greatly improved after the appearance of cisplatin. Recently, paclitaxel has been reported to be effective in the treatment of cisplatin-resistant ovarian cancer. However, control of intraperitoneal lesions is still the biggest problem in this treatment, and attention is focused on the development of effective approaches. Intraperitoneal chemotherapy is considered to be a mode of administration expected to have a direct effect on ovarian cancer by penetrating the tumor and an indirect effect via blood vessels. We examined the outcome and adverse drug reactions in 102 ovarian cancer patients who underwent repeated intraperitoneal administration of cisplatin in our hospital between April 1987 and April 1999. We confirmed that this method may greatly improve the five-year survival rate compared to intravenous administration.

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).

Anti-apolipoprotein A-I autoantibody: characterization of monoclonal autoantibodies from patients with systemic lupus erythematosus

OBJECTIVE

The autoantibody to apolipoprotein A-I (apoA-I), a major constituent of high density lipoproteins (HDL), has been detected in sera of patients with systemic lupus erythematosus (SLE). We established a series of monoclonal anti-apoA-I antibodies (MAAI) from 2 patients with SLE and report the reactivities of MAAI with oxidized HDL, anionic substances, and blood coagulation factors.

METHODS

Peripheral blood B cells from patients with SLE were immortalized by Epstein-Barr virus, and B cells secreting anti-apoA-I antibodies (AAI) were fused with mouse myeloma cells. Six MAAI reactive with human apoA-I in both ELISA and immunoblotting analysis were established. The reactivities of MAAI with HDL, ssDNA and dsDNA, phospholipids such as cardiolipin (CL), and coagulation factors were examined by ELISA.

RESULTS

Although all MAAI bound effectively to apoA-I after the protein had been denatured and transferred to the filter membrane (in immunoblotting analyses), they bound less effectively to apoA-I present in HDL. Both oxidation of HDL in the presence of Mn2+ and an association of apoA-I with autoxidized trilinolein strongly enhanced the binding of MAAI to apoA-I, suggesting that MAAI recognize a defined region of apoA-I, which is exposed upon interacting with oxidatively modified lipids. MAAI showed a functional heterogeneity in their cross-reactivity with self-components: some MAAI were shown to cross-react with anionic substances such as CL and ssDNA, and one MAAI was shown to bind effectively to thrombin.

CONCLUSION

We identified a novel family of AAI that shows preferential binding to apoA-I in oxidatively modified HDL. These AAI are composed of antibodies with heterogeneous cross-reactivities to various self-components such as anionic phospholipids, ssDNA, and thrombin.

Contractile effects and intracellular Ca2+ signalling induced by motilin and erythromycin in the circular smooth muscle of human colon

Motilin has excitatory effects on the colon of the rabbit and the dog, but little is known of its effect on the human colon. The aim of this study was to investigate the effects induced by motilin and erythromycin A (EMA) on muscle strips and on single cells from primary cultures from human colon. Isotonic contraction was recorded in circular muscle strips from macroscopically normal resection specimens of patients operated on for colonic neoplasm. Agonist-induced intracellular Ca2+ ([Ca2+]i) signalling was studied in primary cultures of colonic smooth-muscle cells using the ratiometric Ca2+ indicator Indo 1, on a laser-scanning confocal epifluorescence microscope. In circular muscle strips, norleucine13-porcine motilin ([Nle13]-pm)and EMA induced tonic contractions with an EC50 of 92 +/- 21 nmol L(-1) and 31 +/- 16 micromol L(-1), respectively. The maximal contraction was 21 +/- 4% (motilin) and 33 +/- 12% (EMA) of the response to 10(-4) mol L(-1) acetylcholine (ACh). The motilin antagonist OHM-11526 (10(-5.5) mol L(-1)) abolished the effects of both [Nle13]-pm and EMA. Neither tetrodotoxin (10(-5.5) mol L(-1)), L-nitro-D-arginine methyl ester (L-NAME) (10(-3.5) mol L(-1)) nor guanethidine (10(-5) mol L(-1)) interfered with the effects of [Nle13]-pm or EMA. [Nle13]-pm (10(-11)-10(-6) mol L(-1)) induced rises of [Ca2+]i in cultured colonic myocytes. At 10(-6) mol L-1, 94% of the cells responded, and half of the cells responded at 1.4 nmol L(-1) [Nle13]-pm. 81% (35/43) and 95% (75/79) responded to EMA (10(-6) mol L(-1)) and acetylcholine (ACh, 10(-4) mol L(-1)), respectively. The motilin antagonist GM-109 inhibited motilin- and EMA-induced [Ca2+]i rises. In the absence of extracellular Ca2+, only 13% (7/52) of the cells responded to [Nle13]-pm (10(-6) mol L(-1)) vs. 90% (47/52) to ACh (10(-4) mol L(-1)). Motilin and EMA have direct excitatory effects on circular smooth muscle from the human colon and these effects are mediated via a smooth-muscle motilin receptor. These findings suggest that motilin may regulate colonic motility and that motilides may have therapeutic potential for the treatment of colonic hypomotility.

Design and synthesis of N-terminal cyclic motilin partial peptides: a novel pure motilin antagonist

Motilin antagonist was designed and synthesized on the basis of the structure-activity relationship analysis of porcine motilin that we reported recently. The drug design was performed on a specific concept to reduce a flexibility of peptide conformation of porcine motilin partial peptide by its cyclization. The cyclic peptide was synthesized using Boc (tert-butyloxycarbonyl) solid phase methodology, followed by cyclization using the azide procedure, and tested for the binding activity to motilin receptor and smooth muscle contractile activity. The cyclic peptides 3, 4, and 5 showed antagonistic property on contraction assay (pA2 [the negative logarithm of molar concentration of antagonist causing a 2-hold shift to the right of the concentration-response curve for motilin]: 4.5, 4.34, and 4.04, respectively, in rabbit duodenum) and no contractile activity even at high concentration.

Comparative study of lymphocyte-suppressive potency between prednisolone and methylprednisolone in rheumatoid arthritis

We compared lymphocyte-suppressive potencies of prednisolone and methylprednisolone in rheumatoid arthritis (RA). IC(50)s of the glucocorticoids (GCs) on concanavalin A-induced blastogenesis of peripheral-blood mononuclear cells (PBMCs) from 44 RA patients and 30 healthy subjects were estimated in vitro, and differences in the IC(50)s of the two GCs were evaluated. The mean (+/-SD) IC(50)s for prednisolone and methylprednisolone on PBMC-blastogenesis of RA were 17.2+/-17.1 and 12.6+/-18.4 ng/ml, respectively, and no significant differences were observed between prednisolone-IC(50) and methylprednisolone-IC(50). In contrast, the mean IC(50)s of prednisolone and methylprednisolone on healthy PBMCs were 19.4+/-22. 4 and 3.7+/-3.9 ng/ml, respectively, and thus methylprednisolone potency was significantly higher than prednisolone potency (p<0.01). Methylprednisolone potency against PBMCs in RA patients exhibiting a high level of rheumatoid factor (RF) (>20 IU/ml) and the rheumatoid arthritis particle-agglutination value (RAPA) (>80) was significantly higher than that of patients exhibiting a lower level of RF or RAPA (p<0.05). In prednisolone-IC(50), however, such differences between the two patient-subgroups were not observed. Unlike reported cases of renal transplantation and healthy subjects, there was no difference in the lymphocyte-suppressive potencies for both prednisolone and methylprednisolone on RA-PBMCs. However, PBMCs from RA patients exhibiting high levels of RF or RAPA are more sensitive to methylprednisolone rather than prednisolone.

Neural and muscular receptors for motilin in the rabbit colon

Motilin receptors were classically recognized in the gastroduodenal area, where they help to regulate interdigestive motility. More recently, motilin receptors were identified in the colon where their biologic significance remains unclear. We aimed here to characterize the motilin receptors of the rabbit colon. Distal colon and duodenum were obtained from sacrificed rabbits. Tissues homogenized by Polytron were submitted to differential centrifugation to obtain neural synaptosomes or smooth muscle plasma membranes enriched solutions. Motilin binding to these membranes was determined by the displacement of (125)I MOT by the native peptide MOT 1-22, or by peptide analogues MOT 1-12 [CH(2)NH](10-11) or GM-109 and by erythromycin derivative GM-611. Motilin binding capacity was maximum in colon nerves (49.5 +/- 6.5 fmol/mg protein vs. 19.9 +/- 2.5 in colon muscles or 9.4 +/- 2.8 and 6.6 +/- 1.2 in duodenal muscles and antral nerves respectively); all tissues expressed similar affinity for MOT 1-22, and the motilin agonist GM-611 bound equally to neural or muscle tissues from the rabbit colon; the synthetic antagonist MOT 1-12 [CH(2)NH](10-11) showed greater affinity for colon nerves than for colon muscles (plC50: 7.23 +/- 0.07 vs. 6.75 +/- 0.03). Similar results were obtained with the peptide antagonist GM-109; receptor affinity toward MOT 1-12 [CH(2)NH(10-11)] was always five times superior in neural tissues, whether they came from the colon or the antrum, than in muscle tissues, whether they were obtained from colon or from duodenum. Motilin receptors are found in very high concentration in nerves and in muscles from rabbit colon; specific motilin receptor subtypes are identified in nerves (N) and muscles (M) of the rabbit colon; N and M receptor subtypes seem independent of the organ location.

Structure-activity study of intact porcine motilin

Biologically important sites on intact porcine motilin (pMTL) were explored using its partial peptides. The partial peptides were synthesized using Fmoc (9-fluorenylmethyloxycarbonyl) solid phase methodology, and tested for the binding activity to motilin receptor and the smooth muscle contractile activity. The results were as follows: important residues for the contractile activity were found to be Phe1, Ile4, and Tyr7, and an open space existed beyond the N-terminus between motilin and its receptor. On the model of interaction between motilin and motilin receptor evolved from these results, the three points of interaction, due to Phe1, Ile4, and Tyr7, and the presence of an open space were expected. The motilin agonist and antagonist, designed on this model, will help the inquiry into motilin associated diseases.

Effect of icatibant, a bradykinin B2 receptor antagonist, on the development of experimental ulcerative colitis in mice

Dextran sulfate sodium-induced colitis in mice has been recognized as a model for human ulcerative colitis. Using this model, we carried out a study on the preventive effect of Icatibant, a bradykinin B2 receptor antagonist previously called HOE 140, on the development of colitis. Subcutaneous administration of Icatibant (0.3 or 1.5 mg/kg) significantly suppressed shortening of the large intestine and worsening of the general health. Oral administration of Icatibant (50 mg/kg) significantly suppressed shortening of the large intestine, the onset of diarrhea, and worsening of the general health. In addition, the oral treatment significantly inhibited the development of colitis that was observed histopathologically. These results indicate a role of BK in the development of dextran sulfate sodium-induced colitis in mice, and suggest that BK could be important in human ulcerative colitis.

Frigen II improves the reliability of measurement of interleukin-1 related substances in amniotic fluid

BACKGROUND

To investigate the role of interleukin-1 related substances in amniotic fluid in normal term labor without intrauterine infection.

METHODS

Amniotic fluid samples were collected from forty-one patients with various backgrounds. A novel pre-assay treatment using Frigen II was introduced to improve the recovery rates of cytokines, i.e., interleukin-1alpha, interleukin-1beta and interleukin-1 receptor antagonist, prior to ELISA assay. Urine samples from newborn infants were also tested.

RESULTS

The concentrations of interleukin-1alpha, interleukin-1beta and interleukin-1ra were significantly higher in samples from normal vaginal delivery. The higher levels of interleukin-1alpha were also observed in samples from preterm labor without infection. Preterm infants produced more of interleukin-1 receptor antagonist in urine compared with term infants.

CONCLUSIONS

This study provides evidence of the possible involvement of interleukin-1 related substances in labor without signs of infection. The data from newborn urine suggests that amniotic interleukin-1ra originates from the fetus. However, amniotic fluid interleukin-1alpha and interleukin-1beta may be derived from maternal tissue, such as decidua.

Hypotensive mechanism of [Leu13]motilin in dogs in vivo and in vitro

The effects of [Leu13]motilin were examined in vivo after its intravenous administration into anesthetized dogs and in vitro with isolated preparations of canine mesenteric artery. [Leu13]Motilin (0.1-10 nmol x kg(-1), i.v.) induced both strong and clustered phasic contractions in the gastric antrum and duodenum. At doses of over 1 nmol x kg(-1), [Leu13]motilin also produced transient decreases in arterial blood pressure, left ventricular pressure, maximum rate of rise of left ventricular pressure, and total peripheral resistance, and an increase in aortic blood flow and heart rate. A selective motilin antagonist, GM-109 (Phe-cyclo[Lys-Tyr(3-tBu)-betaAla] trifluoroacetate), completely abolished the gastric antrum and duodenal motor responses induced by [Leu13]motilin. In contrast, hypotension induced by [Leu13]motilin (1 nmol x kg(-1)) was unchanged in the presence of GM-109. In isolated mesenteric artery preparations precontracted with U-46619 (10(-7) M), [Leu13]motilin (10(-8)-10(-5) M) induced an endothelium-dependent relaxation, and this was inhibited by a pretreatment with N(omega)-nitro-L-arginine, a competitive inhibitor of NO synthase (10(-4) M). A high dose (10(-4) M) of GM-109 slightly decreased [Leu13]motilin-induced relaxation, and shifted the concentration-response curve of [Leu13]motilin to the right. However, the pA2 value (4.09) of GM-109 for [Leu13]motilin in the present study was conspicuously lower than that previously demonstrated in the rabbit duodenum (7.37). These results suggest that [Leu13]motilin induces hypotension via the endothelial NO-dependent relaxation mechanism and not through the receptor type that causes upper gastrointestinal contractions.

Involvement of interleukin-1 in the development of ulcerative colitis induced by dextran sulfate sodium in mice

Dextran sulfate sodium (DSS)-induced colitis in mice has been recognized as a model for human ulcerative colitis. Using this model, the effects of anti-murine interleukin 1beta (IL-1beta) antibodies (anti-muIL-1beta) and recombinant murine IL-1 receptor type I (rmuIL-1R) on the development of colitis were examined to determine whether IL-1 plays a role in colitis. Furthermore, RT-PCR amplification was used to examine for the presence of mRNAs for IL-1alpha and IL-1beta in the large intestine. In mice with colitis induced by DSS, administration of anti-muIL-1beta (5 mg/kg, once/week, i.p.) significantly suppressed body weight loss and shortening of the large intestine. Administration of rmuIL-1R (0.2 mg/kg or 1.0 mg/kg, once/day, i.v.) significantly suppressed shortening of the large intestine. Expression of mRNAs for IL-1alpha and IL-1beta was observed in the large intestine of mice which received distilled water containing 3% DSS for 5 days. The expression tended to increase in mice which received DSS for 11 days. In contrast, mRNA expression was not observed in mice which received distilled water without DSS. These results clearly demonstrate that IL-1 is involved in the development of DSS-induced colitis in mice and suggest that downregulation of IL-1 might be useful for the treatment of patients with ulcerative colitis.

Effect of dual inhibition of 5-alpha-reductase and aromatase on spontaneously developed canine prostatic hypertrophy

BACKGROUND

Our aim was to assess the effect of dual inhibition of 5-alpha-reductase and aromatase on prostate glands.

METHODS

We investigated the morphological changes in the prostate gland and the changes in the hormonal environment after administration of finasteride and arimidex to intact canine specimens. The study consisted of four groups: a 5-alpha-reductase only group (5RI only, n = 5); a 5RI plus aromatase-inhibitor combination group (5RI + ARI combination, n = 5); a BPH control group (n = 3); and a castration control group (n = 3). Finasteride (1 mg/kg/day) and the same dose of arimidex were orally administered for 80 days.

RESULTS

In the 5RI group, a significant decrease in the serum dihydrotestosterone (DHT) level was found, and prostatic volume was significantly decreased. However, significant increases in serum testosterone (T) and DHT levels were observed, with a concomitant increase in prostatic volume in the 5RI + ARI combination group. Morphometric analysis showed that histopathological findings in the 5RI + ARI combination group were similar to those in the BPH control group.

CONCLUSIONS

Dual inhibition of 5-alpha-reductase and aromatase resulted in a significant increase in prostate volume, accompanied by a 3-10-fold increase in serum testosterone levels and a significant increase in testicular volume.

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.

Prostaglandin E2 production by endogenous secretion of interleukin-1 in decidual cells obtained before and after the labor

Previous reports revealed that interleukin-1 (IL-1) was involved in the process of premature labor in the cases with intrauterine infection. However, the roles of the cytokine in normal spontaneous labor remain uncertain. The present studies aimed at determining the involvement of the cytokine in prostaglandin (PG)E2 production during labor by the third trimester decidual cells. The cells were obtained at the time of normal spontaneous delivery (NVD) and elective cesarean section (ECS). The NVD cells produced significantly more amount of PGE2 than the ECS cells and the both cells responded to the addition of IL-1 beta to increase PGE2 production. A specific inhibitor of cyclooxygenase-2 (COX-2), NS398, decreased basal PGE2 production and inhibited the stimulatory effect of IL-1 beta in a dose dependent manner in NVD cells. The NVD cells secreted more amount of IL-1 beta than the ECS cells and contained more amount of preprocessed 31kD IL-1 beta inside the cells. The addition of recombinant soluble human IL-1 receptor (type I) not only blocked the effect of IL-1 beta on PG secretion, but significantly reduced the basal production of PGE2 by NVD cells. These results indicate that decidual PG production depends upon COX-2 after the onset of labor. Besides it seems likely that endogenously produced IL-1 beta may be involved in autocrine or paracrine fashion in inducing COX-2 after the onset of labor.

GM-109: a novel, selective motilin receptor antagonist in the smooth muscle of the rabbit small intestine

The pharmacological properties of the cyclic peptide Phe-cyclo[Lys-Tyr(3-tBu)-beta Ala-].trifluoroacetate (GM-109), a selective motilin antagonist, were investigated in the smooth muscle of the rabbit small intestine. GM-109 (0.1-3 microM) competitively inhibited contractions induced by porcine motilin (pMTL) in rabbit isolated duodenum longitudinal strips, with a pA2 value of 7.37 +/- 0.24. However, the contractile response to acetylcholine, to substance P, to prostaglandin F2 alpha and to KCl was unaffected by 10 microM GM-109 in the same preparation. Both GM-109 and pMTL competitively inhibited 125I-pMTL binding to motilin receptors in a homogenate of the rabbit small intestinal smooth muscle tissue. The pKi value of GM-109 and the pKd value of unlabeled pMTL were 7.99 +/- 0.04 and 9.25 +/- 0.06 (each n = 5), respectively. These results indicate that GM-109 is a selective and competitive motilin receptor antagonist in the smooth muscle of the rabbit small intestine. Thus this compound may be a useful pharmacological tool for examining the functional role(s) of motilin.

Properties of single potassium channels in guinea pig hepatocytes

The patch-clamp technique of cell-attached and inside-out configurations was used to study the single potassium channels in isolated guinea pig hepatocytes. The single potassium channels in isolated guinea pig hepatocytes were recorded at different K+ concentrations. A linear single-channel current-voltage relationship was obtained at the voltage range of -80 to -20 mV with slope conductance of 70 +/- 6 pS (n = 10). Under symmetrical high K+ concentration of 148 mM in the cell-attached patch membrane, the I-V curve exhibited a mild inward rectification at potentials positive to + 20 mV. The values of reversal potential was +5 +/- 2 mV (n = 10). When the external potassium concentration ([K+]o) was decreased to 74 mM and 20 mM, the slope conductance was decreased to 48 +/- 2 pS (n = 4) and 24 +/- 3 pS (n = 3), respectively. The reversal potential was changed by 58 mV for a tenfold change in [K+]o, indicating that this channel was highly selective for K+. Open probabilities (Po) of the channel were 73-93% without apparent voltage dependence. The distributions of open time of the channels were fitted to two exponentials, while those of closed time were fitted to three exponentials, exhibiting no voltage dependence. The success rate of K+ channel activity to be recorded was 28% at room temperature, and there were no increases in the success rate nor in the channel opening probabilities at a temperature of 34-36 degrees C. Po in inside-out patches was not changed by application of 1 microM Ca2+ nor 1 mM Mg2+ to the internal side of patch membranes. It is concluded that a novel type of the K+ channels in guinea pig hepatocytes had different properties of slope conductance, channel kinetics, and sensitivity to [Ca2+]i, from those in other species.

An early gallstone clearance following repeat piezoelectric lithotripsy

Piezoelectric extracorporeal litotripsy was performed in 128 symptomatic patients with radiolucent gall-bladder stones to assess the significance of disintegration in fragment clearance. Up to 10 repeat lithotripsy sessions were scheduled to achieve a fragment target size of < 3 mm. Fragmentation assessed by the size of the largest fragments after the last session was graded into three classes. I: sludge-like disintegration, 18%; II: < 3 mm (mean +/- s.d., 1.7 +/- 0.5 mm), 56%; and III: > or = 3 mm (3.3 +/- 0.6), 26%. All patients were initially subjected to lithotripsy alone. Bile acid dissolution therapy was started only when ultrasonography failed to show the evidence of decrease in the < 3 mm fragments during a 1 month follow up. Finally, 69 patients (54%) were treated by lithotripsy alone, and the remaining 59 received additional dissolution therapy at a mean period of 2.5 months after the initial lithotripsy. The rate of complete clearance in class I, II and III patients was 91, 42 and 10% at 6 months and 100, 68 and 49% at 18 months, respectively. Significant differences were noted between the three fragmentation grades (I vs II, III, P < 0.0001; II vs III, P < 0.02). The patients with complete clearance within 6 months were seen only in those treated by lithotripsy alone, while the majority (87%) of patients with complete clearance during the later period were seen in those treated by additional dissolution therapy. We conclude that a high degree of fragmentation appears to lead stones to an earlier period clearance, and reduce the need for dissolution therapy.

Establishment and characterization of stromal cell lines that support differentiation of murine hematopoietic blast cells into osteoclast-like cells

This study aimed to establish and characterize a new stromal cell line that supports the proliferation of hematopoietic blast cells and their differentiation into osteoclast-like cells. Cells isolated from the calvaria of neonatal Balb/c mice were subcultured every 2 to 4 days at 1.2 x 10(4) cells/cm2. After 18 passages the cells had become immortalized and were designated as MCHT-1. MCHT-1 cells were found to support the proliferation of hematopoietic blast cells and their differentiation into osteoclast-like cells when these two cells were co-cultured in the presence of 1 alpha,25(OH)2D3 and dexamethasone. However, because the MCHT-1 cells showed heterogeneity, cloning was performed and each clone was characterized. All the clones obtained supported the proliferation of hematopoietic blast cells and their differentiation into osteoclast-like cells irrespective of their obvious differences in growth capacities and cytochemical characteristics. However, the time-course of the appearance of osteoclast-like cells differed among clones. The supportive effect of these clonal stromal cells on differentiation of hematopoietic blast cells into osteoclast-like cells was completely dependent on the presence of 1 alpha,25(OH)2D3 and dexamethasone. These clonal MCHT-1 cells are expected to be useful for precise analysis of the proliferation and differentiation of osteoclasts.

Comparative studies with 15(R)-15-methylprostaglandin E2 (arbaprostil) in rat femoral arterial preparations in vivo and in vitro

1. The vasodilator responses to 15(R)-15-methylprostaglandin E2 (arbaprostil), prostaglandin (PG) E2 and acetylcholine (ACh) administered into the femoral artery intra-arterial (i.a.) of anesthetized rats were attenuated by i.a. infusion of methylene blue, while that to nicardipine remained unaffected in the same dose-range of methylene blue. 2. The vasocontractor responses to arbaprostil and PGE2 in isolated femoral arterial strips were significantly potentiated by removal of the endothelium and the presence of NG-monomethyl L-arginine, while that to U-46619 remained unaffected under the same condition. 3. The present result indicates that the endothelium-dependent mechanism may play an important role in the vascular response to arbaprostil, like PGE2 and ACh.

Possible role of the endothelium on the vascular response to prostaglandin E2 in rat femoral arterial preparations in vivo and in vitro

The mode of action of prostaglandin E2 was investigated on the rat femoral arterial vascular bed in vivo and on the isolated femoral artery in vitro. In in vivo preparations, prostaglandin E2 (0.01-0.3 microgram), as well as acetylcholine (0.01-0.3 microgram) and nicardipine (0.1-3 micrograms), administered into the femoral artery (i.a.), elicited a dose-dependent increase (vasodilatation) in femoral blood flow, without markedly influencing systemic blood pressure or heart rate. The vasodilator response to prostaglandin E2 was not affected by i.v. pretreatment with atropine (0.5 mg/kg), propranolol (0.5 mg/kg), glibenclamide (20 mg/kg) or NG-monomethyl-L-arginine (100 mg/kg), whereas it was significantly attenuated, like that to acetylcholine, by i.a. infusion of methylene blue. However, methylene blue did not affect the vasodilator response to nicardipine even at a dose sufficient to attenuate the responses to prostaglandin E2 and acetylcholine. In isolated femoral arterial strips, prostaglandin E2 (3 x 10(-8) - 3 x 10(-4) M), phenylephrine (3 x 10(-8) - 1 x 10(-4) M) and U46619 (1 x 10(-9) - 1 x 10(-6) M) induced a concentration-dependent vasoconstriction. The vasoconstrictor responses to prostaglandin E2 and phenylephrine were significantly potentiated by removal of the endothelium and by the presence of methylene blue (3 microM) or NG-monomethyl-L-arginine (100 microM), whereas those to U46619 remained unaffected in the same conditions. The present results indicate that the endothelium may play a role in the vascular response to prostaglandin E2.

A chimeric analog of human and salmon calcitonin eliminates antigenicity and reduces gastrointestinal disturbances

The minimum region in salmon calcitonin (sCT) which induces antigenicity and gastrointestinal disturbances has been identified by examining the cross-reactivity of several sCT fragments and CT analogs with antisera from sCT-treated patients, and by examining inhibition of gastrointestinal motility of these sCT fragments and CT analogs in conscious dogs. Sixteen residues at the N-terminus of sCT comprised the minimum fragment capable of inducing both activities. Human CT (hCT) showed no antigenicity and a four-order weaker inhibition of gastrointestinal motility than sCT. Based on these data, we synthesized the human and salmon chimeric CT, ACT-15, in which the 16 N-terminal residues were those of hCT and the 16 C-terminal residues were those of sCT. ACT-15 had no cross-reactivity with the antisera and had almost the same weak gastrointestinal inhibition effect as hCT in dog and rat models. Nevertheless, it retained a hypocalcemic activity and an analgesic activity comparable to sCT. These results suggest that the amino acid residues in the N-terminal half of CT are responsible for the formation of antibodies and the induction of gastrointestinal disturbances, but may not influence calcium metabolism or analgesia. Clinical studies of ACT-15 will be needed to confirm this hypothesis.

Effects of cisapride on gastrointestinal motor activity and gastric emptying of disopyramide

The effects of cisapride on the gastrointestinal contractile activity and pharmacokinetics of disopyramide were determined in beagle dogs and patients with arrhythmia. In the animal experiments, the gastric motor index was significantly decreased by i.v. administration of disopyramide in a dose-dependent fashion. The peak decrease of the motor index was observed within 5 min after i.v. injection of disopyramide; the motor index then recovered gradually to the level present prior to drug administration. I.v. administration of cisapride (0.5 mg/kg) markedly increased gastrointestinal contractile activity following the decrease induced by disopyramide pretreatment (5 mg/kg, i.v.). In the clinical studies, the gastric emptying test was performed using the acetaminophen method. A significant correlation between plasma concentrations of disopyramide and gastric emptying time has been found (p < 0.001). The combination of disopyramide (100 mg t.i.d.) and cisapride (2.5 mg t.i.d.) significantly increased gastric emptying compared with that induced by disopyramide alone. The peak plasma concentration of disopyramide in association with cisapride oral administration was significantly higher, and the apparent absorption rate constant and lag time of disopyramide were about 2-fold higher and 2-fold shorter, respectively, than for disopyramide alone. Cisapride, acting as a cholinergic agonist, may counteract the anticholinergic effect of disopyramide on gastric motility. As a factor influencing drug absorption, gastric emptying is of importance, as it determines the rate of drug delivery to the small intestine. Therefore, the oral administration of disopyramide with cisapride may be useful for patients with delayed gastric emptying.

Ca(2+)-activated K+ channel is present in guinea-pig but lacking in rat hepatocytes

The mechanisms of norepinephrine-induced membrane responses in isolated hepatocytes from guinea-pigs and rats were compared using the suction-pipette, patch-clamp method, and intracellular Ca2+ concentration ([Ca2+]i) was measured using the Ca2+ fluorescent dye, Quin 2. The resting membrane potentials of isolated guinea-pig hepatocytes were -50 +/- 1 mV (mean +/- SD; n = 38), which is similar to that previously reported in rat hepatocytes by Sawanobori et al. (J Cell Physiol 139: 580-585, 1989). In guinea-pig hepatocytes, norepinephrine (6 microM) caused a membrane hyperpolarization, and norepinephrine (6 microM) or Ca(2+)-ionophore (A23187) (0.4 microM) caused a corresponding outward current. The sensitive current produced by norepinephrine and Ca(2+)-ionophore reversed its polarity at -74 +/- 9 mV (n = 7). The single channel recorded by cell-attached patch and inside-out patch had mean conductance of around 20 + 1 pS and was activated by 1 microM [Ca2+]i. On the other hand, neither norepinephrine (6-20 microM) nor Ca(2+)-ionophore (A 23187) (0.4 microM) caused any change in membrane potential and current in rat hepatocytes, whereas norepinephrine increased [Ca2+]i both in rat and guinea-pig hepatocytes to a similar degree. In the single-channel recording, we recorded single channels that had a mean conductance of 109.8 +/- 17.7 pS different from around 20 pS in guinea-pig. In inside-out patches, increased Ca2+ concentration from 10(-6) to 10(-3) M at the intracellular face of the membrane did not modify the single channel of rat hepatocytes. These results indicate that increased [Ca2+]i activates this channel in guinea-pigs, but that the channel activated by increased [Ca2+]i is lacking in rat hepatocytes membrane. Therefore, different mechanism operates in different species of liver cells to keep the constant state.

Acid-promoted epimerization of arbaprostil, 15(R)-15-methylprostaglandin E2, elicits gastric antisecretory activities in rats

Gastric acid antisecretory activities of 15(R)-15-methylprostaglandin E2 (arbaprostil) preincubated or not preincubated with 0.9% physiological saline, the pH of which was precisely adjusted to less than 4.30, were examined in pylorus-ligated rats, and compared with those of 15(S)-15-methylprostaglandin E2 (15(S), epimer of arbaprostil). 15(S), unlike arbaprostil without preincubation, when s.c.-administered to rats significantly inhibited gastric acid secretion in a dose-dependent manner (30-300 micrograms/kg). However, arbaprostil preincubated at 37 degrees C for 30 min with 0.9% saline, at pHs of 4.30, 2.75 and 1.20, respectively, showed the following order of pH-dependent antisecretory activities: 1.20 greater than 2.75 greater than 4.30. An increase in 15(S) formation from arbaprostil in a pH-dependent manner was also observed by radioisotopic experiments under the same incubation conditions using [3H]-labeled arbaprostil. The present result suggests that the gastric antisecretory effect of arbaprostil can be mainly explained in terms of the formation of 15(S) after oral administration.

Gastric antisecretory activity of 15(R)-15-methylprostaglandin E2, arbaprostil, in dogs

The gastric antisecretory activity of 15(R)-15-methylprostaglandin E2 (arbaprostil) was compared with that of natural prostaglandin (PG) E2 in Pavlov pouch dogs. Arbaprostil significantly inhibited pentagastrin- and food-stimulated gastric secretion when it was administered directly into the pouch at a dose of 10-30 micrograms/pouch and 30-300 micrograms/pouch, respectively. Natural PGE2, however, was inactive up to 1000 micrograms/pouch. The data indicate that arbaprostil is a potent, long-acting orally active antisecretory drug that may be useful for the treatment of peptic ulcer disease.

Separation and purification of uridine diphosphate-glucuronosyltransferases by chromatofocusing on a high-performance liquid chromatograph

A rapid method for the separation and purification of uridine diphosphate-glucuronosyltransferases (GT) was developed with the use of chromatofocusing on a high-performance liquid chromatograph. GT isoenzymes solubilized from hepatic microsomes of Wistar rats were separated on a Mono P column, a pre-packed column for chromatofocusing. Using 4-nitrophenol, testosterone and androsterone as substrates, four fractions with different GT activities were separated in a pH gradient from 9.5 to 7.0. Two isoenzymes, testosterone GT and androsterone GT were purified to apparent homogeneity. They were eluted at pH 8.9 and 8.0 and had subunit molecular weight values of 50000 and 52000, respectively. Approximately 10 mg of solubilized microsomal proteins was applied and the elution was completed within 2 h. Addition of N-nitrodiethylamine, an in vitro activator of GT activity, enhanced the GT activity toward 4-nitrophenol in the three fractions. This chromatographic analysis confirmed the absence of androsterone GT isoenzyme in LA Wistar rats, a mutant strain in terms of androsterone glucuronidation.

Electrophysiological properties of isolated rat liver cells

The electrophysiological properties of isolated rat liver cells were studied using the patch clamp method in whole-cell configuration. The membrane potential in isolated hepatocytes was -42 +/- 7 mV (n = 20). The input resistance (Rin) and the time constant (tau m) were 51 +/- 17 M (the range of 34 to 180 M omega) (n = 20) and 4.2 +/- 1.0 msec (the range of 3 to 16.5 ms) (n = 20). Assuming that the specific membrane capacitance is 1 microF/cm2, the membrane resistance and membrane capacitance were 42. +/- 9.0 K omega cm2 and 87 +/- 27 pF. These values indicate that isolated rat hepatocytes are not abnormally permeable or leaky. The current-voltage relationship was linear with no rectification. The depolarizing pulse from the resting potential did not induce fast or slow inward currents even when norepinephrine or high Ca2 (3.6 mM) were applied. This indicates that there is no voltage-sensitive Ca2+ channel in the isolated hepatocytes.

Effects of administration of N-nitrosodialkylamines and N-nitrodiethylamine on hepatic UDP-glucuronosyltransferase activity in Wistar rats

N-Nitrosodiethylamine (NEN) and N-nitrodiethylamine (NEA) are carcinogens and in vitro activators of hepatic UDP-glucuronosyltransferase (GT) toward 2-aminophenol (AP) and 4-nitrophenol (NP). In this communication, they were intraperitoneally administered to male Wistar rats for 7 days and GT activities were determined towards AP, NP, phenolphthalein (PH) and testosterone (TS). Administration of 30 or 20 mg/kg dose of NEN caused marked decrease of liver and body weights, and did not affect hepatic GT activities. Injection of 10 mg/kg dose of NEN did not diminish liver and body weights, and increased the maximally activated GT activities toward AP and NP. In contrast, 30 mg/kg dose of NEA, did not affect either liver and body weights or GT activities. N-Nitrosodimethylamine (NMN), which is a carcinogen and a weak in vitro AP GT activator, was more toxic than NEN, and 3.6 mg/kg dose of NMN appears to induce GT toward NP and AP. Administration of 46.5 mg/kg N-nitrosodibutylamine (NBN), which is a carcinogen but not a GT activator, did not affect GT activities or liver body weights.

[Receptive relaxation of the canine stomach]

Receptive relaxation of the stomach by feeding was studied in 5 conscious dogs by means of chronically implanted force transducers on the gastric body and antrum. It was found that only the gastric body but not antrum relaxed by feeding, and magnitude of the relaxation of the gastric body was linearly related to the volume (5, 10 and 20 g/kg) of test meals, given once or in multiple times. Secondly, in the study of pharmacological blockers, it was found that atropine, hexamethonium and phentolamine significantly inhibited relaxation, while naloxone and proglumide significantly suppressed relaxation in 3 dogs. Propranolol and domperidone did not influence on receptive relaxation. It is concluded that receptive relaxation of the stomach is mainly mediated through a cholinergic reflex, however, involvement of neurotransmitters other than acetlycholine is suggested in the regulation of receptive relaxation.

Carcinogenicity examination of quercetin and rutin in ACI rats

Carcinogenicity of quercetin and rutin were examined in inbred ACI strain rats. Rats were given a diet containing 1% or 5% quercetin or 5% rutin for 540 days, or 10% quercetin and 10% rutin for 850 days. Rats in control groups were fed a normal basal diet. Most tumors found in experimental groups were also found in the corresponding control groups. Furthermore, there was no significant difference between the incidence of tumors in the experimental or control groups (P greater than 0.05). Thus, quercetin and rutin tested were not shown to be carcinogenic to ACI rats.

Effect of storage on carcinogenic activity of bracken fern

Effect of storage on carcinogenic activity of bracken fern was examined with inbred strain ACI rats of both sexes. The experiment was broken down into 3 groupings: Group I received a diet containing fresh dry bracken powder: Group II received a diet which contained the same dry bracken powder used in Group I but preserved for 1 year at 4 degrees C (Group II-C) or room temperature (Group II-R); Group III received the diet containing bracken powder preserved for 2 years at 4 degrees C (Group III-C) or room temperature (Group III-R). Three control groups corresponding to Groups I, II and III were fed a normal basal diet. Significant differences in incidence of ileal tumors were observed between Group I and both groups of Group III and latent period of intestinal tumors in Group II or III was longer than that of Group I. The results indicate a decreased carcinogenic activity of bracken fern by preservation.

CArcinogenic activity of clivorine, a pyrrolizidine alkaloid isolated from Ligularia dentata

The carcinogenic activity of clivorine, a pyrrolizidine alkaloid isolated from Ligularia dentata, was studied in inbred ACI rats. Twelve animals in the experimental group received a 0.005% solution of clivorine in drinking water for 340 days and survived beyond 440 days after the beginning of the experiment. Of this group, 8 developed tumors in the liver; 2 developed hemangioendothelial sarcomas, and 6 developed neoplastic nodules. The hemangioendothelial sarcoma showed metastasis in the lung of one rat. No tumors were observed in the liver of the control animals.

Chromosomal aberrations and mutation in cultured mammalian cells induced by pyrrolizidine alkaloids

4 pyrrolizidine alkaloids, heliotrine, lasiocarpine, petasitenine, and senkirkine, were tested for their effects of V79 Chinese hamster cells. All the alkaloids produced cytoplasmic vacuolization, and caused cellular and nuclear enlargement. Chromosomal aberrations were induced in cells treated with the alkaloids. Heliotrine and petasitenine induced interchromosomal exchanges, and lasiocarpine and senkirkine caused chromatid gaps. All the alkaloids induced an 8-azaguanine-resistant mutation in V79 cells by direct treatment for 48 h. Mutation was also induced by treatment with the alkaloids for 1 h in the presence of a metabolic activation system.