Suppression of black-hole growth by strong outflows at redshifts 5.8-6.6.

Bright quasars, powered by accretion onto billion-solar-mass black holes, already existed at the epoch of reionization, when the Universe was 0.5-1 billion years old1. How these black holes formed in such a short time is the subject of debate, particularly as they lie above the correlation between black-hole mass and galaxy dynamical mass2,3 in the local Universe. What slowed down black-hole growth, leading towards the symbiotic growth observed in the local Universe, and when this process started, has hitherto not been known, although black-hole feedback is a likely driver4. Here we report optical and near-infrared observations of a sample of quasars at redshifts 5.8 ≲ z ≲ 6.6. About half of the quasar spectra reveal broad, blueshifted absorption line troughs, tracing black-hole-driven winds with extreme outflow velocities, up to 17% of the speed of light. The fraction of quasars with such outflow winds at z ≳ 5.8 is ≈2.4 times higher than at z ≈ 2-4. We infer that outflows at z ≳ 5.8 inject large amounts of energy into the interstellar medium and suppress nuclear gas accretion, slowing down black-hole growth. The outflow phase may then mark the beginning of substantial black-hole feedback. The red optical colours of outflow quasars at z ≳ 5.8 indeed suggest that these systems are dusty and may be caught during an initial quenching phase of obscured accretion5.

A one-generation reproduction toxicity study in rats treated orally with a novel galacto-oligosaccharide.

Galacto-oligosaccharide (GOS) is a naturally occurring prebiotic that beneficially affects the host by selectively stimulating growth and/or activity of one or a limited number of colon bacteria to improve host health. A novel GOS was administered by gavage to male and female Sprague Dawley rats at 0, 500, 1000, and 2000 mg/kg/day for 10 weeks. In males, administration of GOS was initiated prior to mating and continued for 91 days. Females received GOS beginning 2 weeks prior to mating through day 20 of lactation. Parents were observed daily, and body weight (BW) and feed consumption were measured. Vaginal smears, mating behavior, and observation of delivery/lactation were evaluated in parents. Effects on the reproductive function of parents including gonad function, estrous cycle, mating performance, fertility, delivery and lactation, and effects on the growth and development of pups were examined. No deaths occurred, and no general toxicological effects or abnormal reproductive functions were observed in any dose group. Pups were observed at birth and the following measurements were undertaken: BW, external differentiations, sensory functions, and reflex reactions during lactation and just prior to necropsy. No external malformations or differences in the number of pups, in the sex ratio, or BW at birth occurred in any dose group. Growth and development of pups were normal. The No Observed Effect Level for reproductive function of male and female parent animals and for the growth and development of their offspring was at least 2000 mg/kg/day.

A 6-week oral gavage toxicity study of a novel galacto-oligosaccharide in juvenile rats.

A novel galacto-oligosaccharide (GOS) was administered by gavage to groups (10 males and 10 females) of Sprague-Dawley specific pathogen-free rats for 6 weeks from day 4 after birth at doses of 0, 500, 1000, or 2000 mg/kg/day. Each pup was subjected to a variety of observations to examine for development effects/changes after birth: general condition, clinical signs, functional examinations, grip strength and spontaneous movement, body weight and feed consumption, external differentiation, ophthalmological examination, urinalysis (including water consumption), hematology, blood chemistry, necropsy, organ weight, and histopathology. During the study period, no deaths occurred in any group and there were no observed effects from administration of GOS. Therefore, it was concluded that GOS had no effects on the development of animals 4 days after birth. Since, there were no abnormalities due to administration of GOS in the macroscopic examination, organ weight or histopathology of the reproductive organs or differentiation (incisor eruption and eyelid opening) of males or females, it was concluded that repeated oral administration of GOS at 2000 mg/kg/day for 6 weeks from day 4 after birth had : no effects on postnatal development. The no observed effect level of GOS by repeated oral administration for 6 weeks from day 4 after birth was 2000 mg/kg/day for both males and females under the conditions of this study.

Safety of a novel galacto-oligosaccharide: Genotoxicity and repeated oral dose studies.

A series of safety tests were undertaken on a novel galacto-oligosaccharide (GOS) produced from lactose by a two-step enzymatic process involving Sporobolomyces singularis and Kluyveromyces lactis. Bacterial reverse mutation and chromosomal aberration tests, with or without metabolic activation, were performed. These tests showed no mutagenesis in the Ames assay or in Escherichia coli WP2uvrA, and no chromosomal aberrations in cultured fibroblast cells from Chinese hamster lungs (CHL/IU). Micronuclei were not induced in the reticulocytes of mouse peripheral blood following oral administration of GOS. In a 90-day repeated oral dose toxicity study in rats, GOS was administered at 0, 500, 1000 and 2000 mg/kg to male and female Sprague-Dawley rats. There were no GOS-related changes in clinical signs, body weight, water intake, feed intake, urinalysis, ophthalmology, haematology, blood chemistry, organ weights, gross pathology or histopathology in any of the treatment groups compared to the control group. The no observed adverse effect level (NOAEL) of GOS was at least 2000 mg/kg/day in both males and females.

Infection of Rosellinia necatrix with purified viral particles of a member of Partitiviridae (RnPV1-W8).

Isolate W8 of the white root rot fungus, Rosellinia necatrix, harbors three dsRNA segments, L1-, L2- and M-dsRNAs, and showed an irregular colony margin, slow growth, and moderate virulence. The M-dsRNA was previously shown to be the genome of a partitivirus, RnPV1-W8. Here a transfection protocol was developed for RnPV1-W8. Protoplasts of two virus-free isolates of R. necatrix were inoculated with purified viral particles using a polyethylene glycol-mediated method. Virus infection was confirmed by electrophoresis and Northern analysis. RnPV1-W8 introduced into the new host isolates was transmissible via hyphal anastomosis. However, the infection had no effect on the morphology and virulence of infected isolates of R. necatrix. This is the first report on the transfection of a partitivirus for R. necatrix.

Molecular characterization of a partitivirus from the plant pathogenic ascomycete Rosellinia necatrix.

The W8 isolate of the phytopathogenic fungus, Rosellinia necatrix that causes white root rot, contained three segments of double-stranded (ds) RNA, namely L1, L2 and M. Purified viral particles of about 25 nm in diameter contained an RNA segment with almost the same mobility as M-dsRNA, but the band was sensitive to S1 nuclease. Molecular analysis revealed that M-dsRNA consisted of two (RNA 1 and RNA 2) similarly sized species of 2299 and 2279 bp excluding an interrupted poly (A or U) tail of 16-51 bp. The predicted largest open reading frame in RNA 1 and RNA 2 was similar to those of RNA dependent RNA polymerase (RdRp) and coat protein (CP), respectively, encoded by the family Partitiviridae. The non-coding regions (NCR) of the two segments were similar (approximately 70% base identity) at the 5' end, but different at the 3' end. The NCR at the 3' end contained adenosine-uracil rich elements (AREs) in both segments. Northern analyses revealed RNA 1 and RNA 2 in mycelial and viral particle fractions. We coined the name Rosellinia necatrix partitivirus 1-W8 (RnPV1-W8) for M-dsRNA based on viral particle morphology and sequence information.

A Reovirus Causes Hypovirulence of Rosellinia necatrix.

ABSTRACT White root rot, caused by Rosellinia necatrix, is a serious soilborne disease of fruit trees and other woody plants. R. necatrix isolate W370 contains 12 segments of double-stranded RNA (dsRNA) that is believed to represent a possible member of the family Reoviridae. W370 was weakly virulent and its hyphal-tip strains became dsRNA free and strongly virulent. The 12 segments of W370dsRNA were transmitted to hygromycin B-resistant strain RT37-1, derived from a dsRNA-free strain of W370 in all or none fashion through hyphal contact with W370. The W370dsRNA-transmitted strains were less virulent than their parent strain RT37-1 on apple seedlings, with mortality ranging between 0 to 16.7% in apple seedlings that were inoculated with the W370dsRNA-containing strains and 50 to 100% for seedlings inoculated with the dsRNA-free strains. Some W370dsRNA-containing strains killed greater than 16.7% of seedlings, but these were found to have lost the dsRNA in planta. These results indicate that W370dsRNA is a hypovirulence factor in R. necatrix. In addition, a strain lost one segment (S8) of W370dsRNA during subculture, and the S8-deficient mutant strain also exhibits hypovirulence in R. necatrix.

Characteristics of skin wrinkling and dermal changes induced by repeated application of squalene monohydroperoxide to hairless mouse skin.

We have studied the effect of squalene monohydroperoxides (Sq-OOH), initial products of UV-peroxidated squalene, on the skin of hairless mice. Repeated topical application of 10 mM Sq-OOH to hairless mice for 15 weeks induced definite skin wrinkling. When image analysis was used to compare wrinkle formation induced by ultraviolet B (UVB) irradiation and Sq-OOH treatment, the degree of wrinkling in exposed skin was seen to be similar. However, the characteristics of wrinkles induced by either method differed markedly with regard to direction and distribution. Biochemical analysis revealed a significant decrease in collagen content per unit area and mass in Sq-OOH-treated skin, whereas no changes per unit area and decrease in collagen per unit mass were observed in UVB-irradiated skin. As for glycosaminoglycan (GAG) content per unit area, significant increases were observed in both Sq-OOH-treated skin and UVB-irradiated skin. These changes were not induced by organic hydroperoxides such as TERT-butylhydroperoxide or cumene hydroperoxide treatment. Histological observation revealed epidermal hyperplasia and dermal alterations such as collagen degradation and GAG increases in Sq-OOH-treated skin. Histological changes induced by Sq-OOH were not as pronounced as those induced by UVB irradiation. These results clearly suggest that the wrinkling and changes in dermal collagen content induced by Sq-OOH are qualitatively different to those induced by UVB exposure. This may provide a useful model for the study of skin aging, particularly with regard to collagen content.

Sex-dependent toxicity of a novel acyl-CoA:cholesterol acyltransferase inhibitor, YIC-C8-434, in relation to sex-specific forms of cytochrome P450 in rats.

YIC-C8-434 is a novel inhibitor of acyl coenzyme A:cholesterol acyltransferase (ACAT). To clarify the toxicity of YIC-C8-434, the compound was given orally to Sprague-Dawley rats for 28 days at 0, 4, 20, 100, or 500 mg/kg/day. The toxicity of the drug differed significantly between male and female rats. In female rats treated at 500 mg/kg, many symptoms including moribund condition, suppression of weight gain and food consumption, abnormal blood chemistry, and decreases in organ weights (thymus, ovaries, and uterus) were observed. In male rats by contrast, no significant toxicity was observed at any dose. After a single administration of YIC-C8-434 at 500 mg/kg, female rats had a higher blood concentration of the compound than male rats. Little elimination of YIC-C8-434 was observed in female rats on analysis of drug-elimination kinetics. Furthermore, the metabolism of YIC-C8-434 was analyzed using rat hepatic microsomal preparations from both sexes. Consistent with the observations in vivo, hepatic microsomes from male rats better metabolized YIC-C8-434 than those from females. In addition, the metabolism of YIC-C8-434 by hepatic microsomes from male rats was blocked by SKF525A, a P450 inhibitor. Inhibition experiments using anti-rat CYP1A1, CYP1A2, CYP2B1, CYP2C11, CYP2E1, CYP3A2, and CYP4A1 antisera indicated that CYP3A2 played the predominant role in the metabolism of YIC-C8-434 in rats. Since there is less CYP3A2 in the liver of female than male rats, the involvement of CYP3A2 in YIC-C8-434 metabolism has implications for the sex-related metabolic activity and toxicity of YIC-C8-434.

Intravenous cyclosporine and tacrolimus caused anaphylaxis but oral cyclosporine capsules were tolerated in an allogeneic bone marrow transplant recipient.

A Japanese female patient with angioimmunoblastic T cell lymphoma underwent allogeneic bone marrow transplantation (BMT) from her brother. Cyclosporine at a dose of 3 mg/kg was started by continuous infusion over 24 h on day -1 of BMT. Within a couple of minutes after the infusion was begun, she developed diffuse pruritic erythema on her whole body and tachycardia. The infusion was immediately stopped and corticosteroid was given, resulting in disappearance of the erythema gradually. She was then switched to intravenous tacrolimus. However, she suffered urticalial erythema again. Since polyoxyethylated castor oil, a solubilizer used in the injective formulation of both cyclosporine and tacrolimus, is considered to be responsible for the reaction, she was given oral capsules of cyclosporine (Sandimmun) in which polyoxyethylated castor oil was not contained. No further anaphylactic reaction was observed. The BM cells were successfully engrafted without causing severe GVHD. She was discharged on cyclosporine capsules without any further adverse effects. Anaphylaxis to intravenous cyclosporine and tacrolimus is a very rare but a serious complication. Our present case indicates that oral capsule of Sandimmun is a safe alternative to prevent GVHD in such a case of anaphylactic reaction against intravenous formulation.

Changes in the levels of glutathione after cellular and cutaneous damage induced by squalene monohydroperoxide.

Squalene monohydroperoxide (Sq-OOH), the initial product of ultraviolet-peroxidated squalene, was used to investigate the effect of peroxidative challenge upon the glutathione contents in rabbit ear skin and primary-cultured fibroblasts derived from rabbit ear skin. The cellular reduced glutathione (GSH) contents decreased during 30-minute incubations in vitro with Sq-OOH, and oxidized glutathione (GSSG) was formed concomitantly, indicating that Sq-OOH had a potential for GSH-depleting activity in vitro. When Sq-OOH was applied topically to the skin in vivo, only GSSG contents increased significantly within 30 minutes. Moreover, pretreatment with the GSH depletors, DL-buthionine sulfoximine (BSO) and diethyl maleate (DEM), could potentiate the cytotoxicity and comedogenicity induced by Sq-OOH. These findings suggest that the endogenous antioxidant, glutathione, is quite sensitive to Sq-OOH and may be an important material for protecting cells and/or tissues against the oxidative stress induced by Sq-OOH treatment.

Intestinal microflora are necessary for development of spontaneous adenocarcinoma of the large intestine in T-cell receptor beta chain and p53 double-knockout mice.

This study was conducted to confirm the hypothesis that intestinal microflora are required for the development of adenocarcinoma in the colon of the TCRbeta and p53 double-knockout (TCRbeta-/- p53-/-) mouse. Germ-free TCRbeta-/- p53-/- mice were produced. At 7 weeks of age, the animals were divided into two groups (n = 10/group), and one of these groups was conventionalized. Animals of both groups were subjected to histopathological examination for adenocarcinoma of the colon at 4 months of age. There was no development of adenocarcinoma of the colon among the germ-free mice, whereas in the conventionalized group, adenocarcinomas of the ileocecum and cecum were detected in 70% of animals. These results indicate the usefulness of the TCRbeta-/- p53-/- mouse as a colon cancer animal model that develops spontaneous adenocarcinoma of the colon early in life, and suggest that intestinal microflora play a major role in the development of adenocarcinoma of the colon in this animal model.

A mucinous histochemical study on malignancy of aberrant crypt foci (ACF) in rat colon.

The relationship between malignancy and number of crypts (crypt multiplicity) comprising aberrant crypt foci (ACF) was investigated, by studying changes in the mucous nature of ACF with 5 crypts or less, ACF with 6-13 crypts, adenomas and invasive adenocarcinomas induced by 1,2-dimethylhydrazine in distal colon of rats. A paradoxical Con A-staining was performed for goblet cell mucins. Of the sulfomucin-dominant ACF with 1-3 crypts, 82.6% had labile class III mucin, similar to the distal colon in the normal rats. However, in most of the goblet cell mucin produced by the ACF with 4-5 crypts with an indicated relation to colorectal carcinoma or the sialomucin (SiM) -dominant ACF with 1-3 crypts, mucin types other than class I were rarely present. The incidence of class I mucin decreased with the increase in crypt multiplicity of ACF or in the degree of histological malignancy, with the lowest incidence of 40% in adenocarcinomas. In contrast, the incidence of class II mucin increased markedly with the increase in crypt multiplicity of ACF or in the degree of histological malignancy, with the highest incidence in adenocarcinomas (95%). The ACF with 6-13 crypts had a mucous profile similar to that of adenomas. These results suggested that malignancy of ACF related to the crypt multiplicity. In the ACF with 1-3 crypts, SiM-dominant ACF had the potential to progress to malignant lesions.

Modified irinotecan hydrochloride (CPT-11) administration schedule improves induction of delayed-onset diarrhea in rats.

PURPOSE: Clinically, diarrhea is the major dose-limiting toxicity of irinotecan hydrochloride (CPT-11). Using a rat model, we attempted to decrease the incidence of delayed-onset diarrhea by modifying the administration schedule of CPT-11, and studied the pharmacokinetics in this model in relation to the incidence of diarrhea. METHODS: CPT-11 (total dose, 240 mg/kg) was administered intravenously (i.v.) to rats according to various schedules, and the incidence of delayed-onset diarrhea was monitored. RESULTS: Administration of CPT-11 at a dose of 60 mg/kg once daily for four consecutive days induced severe diarrhea, while at 30 mg/kg twice daily at an interval of 9 h (daily dose 60 mg/kg) for four consecutive days alleviated the diarrheal symptoms, and at 30 or 40 mg/kg once daily for eight or six consecutive days, respectively. diarrhea was hardly induced. With the first schedule, mucosal impairment of the cecal epithelium was observed, including wall thickening, edema, decrease in crypt number and size, and formation of pseudomembrane-like substance, whereas these changes were less severe with the second schedule and were hardly observed with the other two schedules. The areas under the plasma and cecal tissue concentration-time curves (AUCpla and AUCcec), the maximum plasma concentrations (Cmax) and the biliary excretions of CPT-11 and its metabolites, 7-ethyl-10-hydroxycamptothecin (SN-38) and SN-38 glucuronide (SN-38G) in rats depended on the daily dose of CPT-11. Exceptionally, CPT-11 Cmax was significantly lower and SN-38 AUCcec was larger in the animals treated at 30 mg/kg twice daily than in those treated at 60 mg/kg once daily. CONCLUSION: These results suggested that the duration of exposure to both CPT-11 and SN-38 of the intestinal epithelium and CPT-11 plasma Cmax are closely related to the incidence and severity of CPT-11-induced delayed-onset diarrhea in rats.

Comedogenicity of squalene monohydroperoxide in the skin after topical application.

The comedogenicity of squalene peroxides was examined on the rabbit ear skin after topical application of squalene-monohydroperoxide (Sq-OOH), the initial product when squalene was irradiated with UV-A. Since comedogenic products from UV-irradiated squalene were extracted with methanol solution, we isolated Sq-OOH by reverse-phased HPLC with a methanol mobile phase solvent. The degree of comedogenic reaction induced by Sq-OOH was higher than that of well-known comedogenic cosmetic ingredients. Unlike two other mono-peroxides, tert-butyl hydroperoxide and cumene-mono-hydroperoxide, Sq-OOH induced comedo-formation in the rabbit ear skin. However, the comedogenicity of reduced Sq-OOH, squalene-hydroxide (Sq-OH) and squalene itself was lower than that of Sq-OOH. These results indicate that Sq-OOH is a potent comedogenic mono-hydroperoxide chemical to rabbit skin.

No toxicity caused by organ accumulation of CPT-11 on multiple injections under clinical regimens in rats.

We investigated the accumulation of CPT-11 and its metabolite (SN-38) in various organs and toxicities on multiple injections of CPT-11 under clinical regimens in SD rats. CPT-11 (16.7 mg/kg equivalent to 100 mg/m2) was administered intravenously by a single injection, or by multiple injections in 1 course (once a week for three consecutive weeks) or 3 courses (1 course repeated 3 times at intervals of 2 weeks). There was no tendency for CPT-11 and SN-38 to accumulate in any organs regardless of the number of injections. Treatment-related changes were not observed in the general condition, body weight, hematology, biochemistry, and organ weights. Histopathological changes induced by CPT-11 were not persistent and the rats made a rapid recovery after the administrations. From these results, it is suggested that there is no toxicity caused by accumulation of CPT-11 and its active metabolite, SN-38, in organs under clinical regimens in rats.

Skin roughness and wrinkle formation induced by repeated application of squalene-monohydroperoxide to the hairless mouse.

The present study examines the cumulative effects of sub-erythema application of squalene-monohydroperoxide (Sq-OOH), the initial products of UV-peroxidated squalene, to the skin of hairless mice. Sq-OOH was isolated by the methanol extraction and preparative HPLC method. Repeated topical application of 10 mM Sq-OOH to hairless mice for 3 weeks induced definite skin roughness and crinkle formation. 3-D surface parameter analysis revealed changes in all roughness parameters (number of furrows and crests, distance between a furrow and next crest, and irregularity) of the group treated with more than 3 mM Sq-OOH compared to the control group. These skin surface changes were not induced by squalene, squalene-monohydroxide (Sq-OH) or organic hydroperoxides such as tert-butyl hydroperoxide and cumene-hydroperoxide at 10 mM. Similarly, such changes were not induced by primary irritants, such as sodium lauryl sulfate and n-tetradecane under the same experimental conditions. Skin conductance decreased, following application of 10 mM Sq-OOH. Histological observation revealed that application of 10 mM Sq-OOH induced slight hyperkeratosis, moderate epidermal thickening and slight hyperplasia of sebaceous glands.

Interferon-alpha therapy for children with chronic hepatitis C.

We followed 53 children with chronic hepatitis C for more than 3 years. Spontaneous remission occurred only 3 (6%) in whom the serum titer of HCV-RNA was low. We considered interferon (IFN) should be adopted in all children with chronic hepatitis C but those who expected to be remitted spontaneously. We evaluated the effect of IFN therapy on 32 children and investigated factors that may influence the outcome of the treatment. A complete response was obtained in 13 children (41%). IFN was well tolerated.

A new meiotic endonuclease from Coprinus meiocytes.

Two different types of Coprinus meiotic nuclease have been previously reported by the authors which are believed to be involved in meiotic chromosome recombination [1,2]. A third meiotic endonuclease was purified from the cap tissues of the basidiocarp of Coprinus cinereus. The enzyme is a 60 kDa molecule composed of a monopolypeptide as revealed by SDS-PAGE and FPLC-Sephacryl S-300 gel filtration. The enzyme belongs to a type of endonuclease which can preferentially digest single-stranded DNA and requires divalent cations as a co-factor, most commonly Mg2+ ions. In the presence of this co-factor, the enzyme converts the supercoiled plasmid DNA (form I) to both the relaxed form (form II) and the linear form (form III). Ca2+ ions can also function as a co-factor, though, in this case, not only is form I plasmid converted to form II, but a few ladder bands between form I and form II are also produced. The Ca2+ ion effect as a cofactor can be prevented with ATP. Immunohistochemical observation shows that the enzyme is distributed in the surface of the gills, which contain the meiotic tissues. These characteristics clearly differ from those of the meiotic nucleases reported previously.