Cancer chemopreventive activity of resveratrol, a natural product derived from grapes

Resveratrol, a phytoalexin found in grapes and other food products, was purified and shown to have cancer chemopreventive activity in assays representing three major stages of carcinogenesis. Resveratrol was found to act as an antioxidant and antimutagen and to induce phase II drug-metabolizing enzymes (anti-initiation activity); it mediated anti-inflammatory effects and inhibited cyclooxygenase and hydroperoxidase functions (antipromotion activity); and it induced human promyelocytic leukemia cell differentiation (antiprogression activity). In addition, it inhibited the development of preneoplastic lesions in carcinogen-treated mouse mammary glands in culture and inhibited tumorigenesis in a mouse skin cancer model. These data suggest that resveratrol, a common constituent of the human diet, merits investigation as a potential cancer chemopreventive agent in humans.

IL-17s adopt a cystine knot fold: structure and activity of a novel cytokine, IL-17F, and implications for receptor binding

The proinflammatory cytokine interleukin 17 (IL-17) is the founding member of a family of secreted proteins that elicit potent cellular responses. We report a novel human IL-17 homolog, IL-17F, and show that it is expressed by activated T cells, can stimulate production of other cytokines such as IL-6, IL-8 and granulocyte colony-stimulating factor, and can regulate cartilage matrix turnover. Unexpectedly, the crystal structure of IL-17F reveals that IL-17 family members adopt a monomer fold typical of cystine knot growth factors, despite lacking the disulfide responsible for defining the canonical "knot" structure. IL-17F dimerizes in a parallel manner like neurotrophins, and features an unusually large cavity on its surface. Remarkably, this cavity is located in precisely the same position where nerve growth factor binds its high affinity receptor, TrkA, suggesting further parallels between IL-17s and neurotrophins with respect to receptor recognition.

Chemical oxidation and DNA damage catalysed by inorganic sunscreen ingredients

Titanium dioxide (TiO2) has been noted (US Federal Register, 43FR38206, 25 August 1978) to be a safe physical sunscreen because it reflects and scatters UVB and UVA in sunlight. However, TiO2 absorbs about 70% of incident UV, and in aqueous environments this leads to the generation of hydroxyl radicals which can initiate oxidations. Using chemical methods, we show that all sunscreen TiO2 samples tested catalyse the photo-oxidation of a representative organic substrate (phenol). We also show that sunlight-illuminated TiO2 catalyses DNA damage both in vitro and in human cells. These results may be relevant to the overall effects of sunscreens.

What childhood obesity prevention programmes work? A systematic review and meta-analysis

Previous reviews of childhood obesity prevention have focused largely on schools and findings have been inconsistent. Funded by the US Agency for Healthcare Research and Quality (AHRQ) and the National Institutes of Health, we systematically evaluated the effectiveness of childhood obesity prevention programmes conducted in high-income countries and implemented in various settings. We searched MEDLINE®, Embase, PsycINFO, CINAHL®, ClinicalTrials.gov and the Cochrane Library from inception through 22 April 2013 for relevant studies, including randomized controlled trials, quasi-experimental studies and natural experiments, targeting diet, physical activity or both, and conducted in children aged 2-18 in high-income countries. Two reviewers independently abstracted the data. The strength of evidence (SOE) supporting interventions was graded for each study setting (e.g. home, school). Meta-analyses were performed on studies judged sufficiently similar and appropriate to pool using random effect models. This paper reported our findings on various adiposity-related outcomes. We identified 147 articles (139 intervention studies) of which 115 studies were primarily school based, although other settings could have been involved. Most were conducted in the United States and within the past decade. SOE was high for physical activity-only interventions delivered in schools with home involvement or combined diet-physical activity interventions delivered in schools with both home and community components. SOE was moderate for school-based interventions targeting either diet or physical activity, combined interventions delivered in schools with home or community components or combined interventions delivered in the community with a school component. SOE was low for combined interventions in childcare or home settings. Evidence was insufficient for other interventions. In conclusion, at least moderately strong evidence supports the effectiveness of school-based interventions for preventing childhood obesity. More research is needed to evaluate programmes in other settings or of other design types, especially environmental, policy and consumer health informatics-oriented interventions.

Oxidative stress and diabetic cardiomyopathy: a brief review

Diabetes is a serious public health problem. Improvements in the treatment of noncardiac complications from diabetes have resulted in heart disease becoming a leading cause of death in diabetic patients. Several cardiovascular pathological consequences of diabetes such as hypertension affect the heart to varying degrees. However, hyperglycemia, as an independent risk factor, directly causes cardiac damage and leads to diabetic cardiomyopathy. Diabetic cardiomyopathy can occur independent of vascular disease, although the mechanisms are largely unknown. Previous studies have paid little attention to the direct effects of hyperglycemia on cardiac myocytes, and most studies, especially in vitro, have mainly focused on the molecular mechanisms underlying pathogenic alterations in vascular smooth-muscle cells and endothelial cells. Thus, a comprehensive understanding of the mechanisms of diabetic cardiomyopathy is urgently needed to develop approaches for the prevention and treatment of diabetic cardiac complications. This review provides a survey of current understanding of diabetic cardiomyopathy. Current consensus is that hyperglycemia results in the production of reactive oxygen and nitrogen species, which leads to oxidative myocardial injury. Alterations in myocardial structure and function occur in the late stage of diabetes. These chronic alterations are believed to result from acute cardiac responses to suddenly increased glucose levels at the early stage of diabetes. Oxidative stress, induced by reactive oxygen and nitrogen species derived from hyperglycemia, causes abnormal gene expression, altered signal transduction, and the activation of pathways leading to programmed myocardial cell deaths. The resulting myocardial cell loss thus plays a critical role in the development of diabetic cardiomyopathy. Advances in the application of various strategies for targeting the prevention of hyperglycemia-induced oxidative myocardial injury may be fruitful.

Integration of spatial and single-cell transcriptomic data elucidates mouse organogenesis

Molecular profiling of single cells has advanced our knowledge of the molecular basis of development. However, current approaches mostly rely on dissociating cells from tissues, thereby losing the crucial spatial context of regulatory processes. Here, we apply an image-based single-cell transcriptomics method, sequential fluorescence in situ hybridization (seqFISH), to detect mRNAs for 387 target genes in tissue sections of mouse embryos at the 8-12 somite stage. By integrating spatial context and multiplexed transcriptional measurements with two single-cell transcriptome atlases, we characterize cell types across the embryo and demonstrate that spatially resolved expression of genes not profiled by seqFISH can be imputed. We use this high-resolution spatial map to characterize fundamental steps in the patterning of the midbrain-hindbrain boundary (MHB) and the developing gut tube. We uncover axes of cell differentiation that are not apparent from single-cell RNA-sequencing (scRNA-seq) data, such as early dorsal-ventral separation of esophageal and tracheal progenitor populations in the gut tube. Our method provides an approach for studying cell fate decisions in complex tissues and development.

Compounds from Syzygium aromaticum possessing growth inhibitory activity against oral pathogens

A crude MeOH extract of Syzygium aromaticum (clove) exhibited preferential growth-inhibitory activity against Gram-negative anaerobic periodontal oral pathogens, including Porphyromonas gingivalis and Prevotella intermedia. By means of bioassay-directed chromatographic fractionation, eight active compounds were isolated from this extract and were identified as 5,7-dihydroxy-2-methylchromone 8-C-beta-D-glucopyranoside, biflorin, kaempferol, rhamnocitrin, myricetin, gallic acid, ellagic acid, and oleanolic acid, based on spectroscopic evidence. The antibacterial activity of these pure compounds was determined against Streptococcus mutans, Actinomyces viscosus, P. gingivalis, and P. intermedia. The flavones, kaempferol and myricetin, demonstrated potent growth-inhibitory activity against the periodontal pathogens P. gingivalis and P. intermedia.

Metallothionein in radiation exposure: its induction and protective role

Since its discovery about 40 years ago, there has been a wide interdisciplinary research interest in metallothionein (MT) on its physiological and toxicological aspects. Functionally, MT is involved not only in metal detoxification and homeostasis, but also in scavenging free radicals during oxidative damage. Among over 4500 publications which can be retrieved by Medline search, only about 50 reports have been published on the relationship of MT with ionizing and UV radiation. In this review, we have evaluated critically the published data on the induced synthesis of MT by radiation, and the potential functions of MT in radiation induced cell damage. MT mRNA expression or MT synthesis was found to be induced by exposure of cells in vitro or tissues in vivo to ionizing or UV radiation. In most of the studies in animals and tissue cultures, high doses of ionizing radiation were used to induce MT, and, therefore, it is difficult to extrapolate these results to low level of repeated exposures to radiation in humans. Induced synthesis of MT is considered as one of the mechanisms involved in the adaptive response to low dose radiation exposure. The presence of MT in normal cells may provide protective effects from radiation-induced genotoxicity and cytotoxicity. However, in tumor cells, the presence of MT can result in drug and radiation resistance as well. These effects are modulated by other cellular factors, besides MT, such as antioxidants, and by the cell cycle stages in cell proliferation and differentiation.

Crystal structure of a four-stranded intercalated DNA: d(C4)

The crystal structure of d(C4) solved at 2.3-A resolution reveals a four-stranded molecule composed of two interdigitated or intercalated duplexes. The duplexes are held together by hemiprotonated cytosine-cytosine base pairs and are parallel stranded, but the two duplexes point in opposite directions. The molecule has a slow right-handed twist of 12.4 degrees between covalently linked cytosine base pairs, and the base stacking distance is 3.1 A. This is in general agreement with the NMR studies. A biological role for DNA in this conformation is suggested.

Didymellaceae revisited

The Didymellaceae is one of the most species-rich families in the fungal kingdom, and includes species that inhabit a wide range of ecosystems. The taxonomy of Didymellaceae has recently been revised on the basis of multi-locus DNA sequence data. In the present study, we investigated 108 Didymellaceae isolates newly obtained from 40 host plant species in 27 plant families, and various substrates from caves, including air, water and carbonatite, originating from Argentina, Australia, Canada, China, Hungary, Israel, Italy, Japan, South Africa, the Netherlands, the USA and former Yugoslavia. Among these, 68 isolates representing 32 new taxa are recognised based on the multi-locus phylogeny using sequences of LSU, ITS, rpb2 and tub2, and morphological differences. Within the Didymellaceae, five genera appeared to be limited to specific host families, with other genera having broader host ranges. In total 19 genera are recognised in the family, with Heracleicola being reduced to synonymy under Ascochyta. This study has significantly improved our understanding on the distribution and biodiversity of Didymellaceae, although the placement of several genera still need to be clarified.

Induction of cytogenetic adaptive response of somatic and germ cells in vivo and in vitro by low-dose X-irradiation

The cytogenetic adaptive response induced by low-level radiation was studied using human and rabbit lymphocytes in vitro and bone marrow cells and germ cells in vivo. The inductive dose of X-rays was 10 mGy for the in vitro studies at a dose rate of 10 mGy/min, and 2, 10, 50, 75 and 100 mGy for the in vivo studies at a dose rate of 50 mGy/min. The challenging dose was 1.5 Gy X-rays for the in vitro experiments and 0.65 or 0.75 Gy for the in vivo experiments at a dose rate of 0.44 Gy/min. The results reported here, in addition to those that have appeared in the literature, show the following characteristics documented for the first time: (1) 10 mGy could induce the adaptive response in human as well as rabbit lymphocytes irradiated not only in G1, S and G2 phases, but also in the Go state; (2) although the induced adaptive response could only last three cell cycles, it could be revived when the inductive dose was repeated after the third cell cycle; (3) the adaptive response could be induced by low-dose X-rays in somatic cells, both in vitro (lymphocytes) and in vivo (bone marrow cells), and also in germ cells (spermatocytes); (4) the magnitude of the adaptive response induced by whole-body irradiation was found to be dose-dependent--the lower the inductive dose the more the reduction of the frequency of chromatid aberrations following the challenging dose.

Metallothionein inhibits peroxynitrite-induced DNA and lipoprotein damage

Previous studies have demonstrated that metallothionein functions as an antioxidant that protects against oxidative DNA, protein, and lipid damage induced by superoxide anion, hydrogen peroxide, hydroxyl radical, and nitric oxide. The present study was undertaken to test the hypothesis that metallothionein also protects from DNA and lipoprotein damage induced by peroxynitrite, an important reactive nitrogen species that causes a diversity of pathological processes. A cell-free system was used. DNA damage was detected by the mobility of plasmid DNA in electrophoresis. Oxidation of low density lipoprotein was measured by a thiobarbituric acid-reactive substance, which was confirmed by lipid hydroperoxide assay. Plasmid DNA damage and low density lipoprotein oxidation were induced by 3-morpholinosydnomine, which produces peroxynitrite through the reaction between nitric oxide and superoxide anion or by synthesized peroxynitrite directly. DNA damage by 3-morpholinosydnomine was prevented by both metallothionein and superoxide dismutase, whereas the damage caused by peroxynitrite was prevented by metallothionein only. The oxidation of low density lipoprotein by 3-morpholinosydnomine and peroxynitrite was also significantly inhibited by metallothionein. This study thus demonstrates that metallothionein may react directly with peroxynitrite to prevent DNA and lipoprotein damage induced by this pathological reactive nitrogen species.

Apoptotic germ-cell death and testicular damage in experimental diabetes: prevention by endothelin antagonism

This paper explores the role of endothelins (ETs) in diabetes-induced testicular damage by investigating, in a temporal manner, testes from streptozotocin (STZ)-induced diabetic rats. Testicular and epididymal weights and testicular morphology were assessed. Cell death was evaluated by light microscopy using conventional staining and morphology, and by apoptotic cell staining using the Terminal deoxynucleotidyl transferase-mediated dUTP Nick End-Labeling (TUNEL) technique. Expression of endothelin-1 (ET-1) mRNA was evaluated by a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) method. Furthermore, effects of a mixed ETA and ETB receptor antagonist, bosentan, were studied. Testicular weights did not show any change at 1 month of follow-up, but were decreased after 6 months of diabetes. However, epididymal weights were significantly decreased at the end of both time periods in the diabetic rats. Morphological evaluations of the testes from diabetic rats showed a reduction in seminiferous tubular diameter, an increase in the number of empty testicular tubules and an increase in vascular density. Furthermore, degenerated germ cells and TUNEL-positive cells were significantly higher in diabetic rats than in control animals. The changes in diabetic animals were associated with increased ET-1 mRNA expression and were prevented by bosentan treatment. Administration of bosentan prevented decreased testicular weights, reduced seminiferous tubule diameters, increased vascular densities and incidences of degenerated and apoptotic germ cells and empty tubules in diabetic rats at the long-term follow-up. These results demonstrated that an ET-1 mediated pathway might be involved in testicular injury and germ-cell apoptosis in diabetes.

Regulatory potential for concerted modulation of Nrf2- and Nfkb1-mediated gene expression in inflammation and carcinogenesis

Many studies have implicated nuclear factor E2-related factor 2 (Nrf2) and nuclear factor-kappaB1 (Nfkb1) in inflammation and cancer. However, the regulatory potential for crosstalk between these two important transcription factors in inflammation and carcinogenesis has not been explored. To delineate conserved transcription factor-binding site signatures, we performed bioinformatic analyses on the promoter regions of human and murine Nrf2 and Nfkb1. We performed multiple sequence alignment of Nrf2 and Nfkb1 genes in five mammalian species - human, chimpanzee, dog, mouse and rat - to explore conserved biological features. We constructed a canonical regulatory network for concerted modulation of Nrf2 and Nfkb1 involving several members of the mitogen-activated protein kinase (MAPK) family and present a putative model for concerted modulation of Nrf2 and Nfkb1 in inflammation/carcinogenesis. Our results reflect potential for putative crosstalk between Nrf2 and Nfkb1 modulated through the MAPK cascade that may influence inflammation-associated etiopathogenesis of cancer. Taken together, the elucidation of potential relationships between Nrf2 and Nfkb1 may help to better understand transcriptional regulation, as well as transcription factor networks, associated with the etiopathogenesis of inflammation and cancer.

Misexpression of basic helix-loop-helix genes in the murine cerebral cortex affects cell fate choices and neuronal survival

To investigate the role(s) of basic helix-loop-helix genes (bHLH) genes in the developing murine cerebral cortex, Mash1, Math2, Math3, Neurogenin1 (Ngn1), Ngn2, NeuroD, NeuroD2 and Id1 were transduced in vivo into the embryonic and postnatal cerebral cortex using retrovirus vectors. The morphology and location of infected cells were analyzed at postnatal stages. The data indicate that a subset of bHLH genes are capable of regulating the choice of neuronal versus glial fate and that, when misexpressed, they can be deleterious to the survival of differentiating neurons, but not glia.

Fungal Planet description sheets: 951-1041

Novel species of fungi described in this study include those from various countries as follows: Antarctica, Apenidiella antarctica from permafrost, Cladosporium fildesense from an unidentified marine sponge. Argentina, Geastrum wrightii on humus in mixed forest. Australia, Golovinomyces glandulariae on Glandularia aristigera, Neoanungitea eucalyptorum on leaves of Eucalyptus grandis, Teratosphaeria corymbiicola on leaves of Corymbia ficifolia, Xylaria eucalypti on leaves of Eucalyptus radiata. Brazil, Bovista psammophila on soil, Fusarium awaxy on rotten stalks of Zea mays, Geastrum lanuginosum on leaf litter covered soil, Hermetothecium mikaniae-micranthae (incl. Hermetothecium gen. nov.) on Mikania micrantha, Penicillium reconvexovelosoi in soil, Stagonosporopsis vannaccii from pod of Glycine max. British Virgin Isles, Lactifluus guanensis on soil. Canada, Sorocybe oblongispora on resin of Picea rubens. Chile, Colletotrichum roseum on leaves of Lapageria rosea. China, Setophoma caverna from carbonatite in Karst cave. Colombia, Lareunionomyces eucalypticola on leaves of Eucalyptus grandis. Costa Rica, Psathyrella pivae on wood. Cyprus, Clavulina iris on calcareous substrate. France, Chromosera ambigua and Clavulina iris var. occidentalis on soil. French West Indies, Helminthosphaeria hispidissima on dead wood. Guatemala, Talaromyces guatemalensis in soil. Malaysia, Neotracylla pini (incl. Tracyllales ord. nov. and Neotracylla gen. nov.) and Vermiculariopsiella pini on needles of Pinus tecunumanii. New Zealand, Neoconiothyrium viticola on stems of Vitis vinifera, Parafenestella pittospori on Pittosporum tenuifolium, Pilidium novae-zelandiae on Phoenix sp. Pakistan, Russula quercus-floribundae on forest floor. Portugal, Trichoderma aestuarinum from saline water. Russia, Pluteus liliputianus on fallen branch of deciduous tree, Pluteus spurius on decaying deciduous wood or soil. South Africa, Alloconiothyrium encephalarti, Phyllosticta encephalarticola and Neothyrostroma encephalarti (incl. Neothyrostroma gen. nov.) on leaves of Encephalartos sp., Chalara eucalypticola on leaf spots of Eucalyptus grandis × urophylla, Clypeosphaeria oleae on leaves of Olea capensis, Cylindrocladiella postalofficium on leaf litter of Sideroxylon inerme, Cylindromonium eugeniicola (incl. Cylindromonium gen. nov.) on leaf litter of Eugenia capensis, Cyphellophora goniomatis on leaves of Gonioma kamassi, Nothodactylaria nephrolepidis (incl. Nothodactylaria gen. nov. and Nothodactylariaceae fam. nov.) on leaves of Nephrolepis exaltata, Falcocladium eucalypti and Gyrothrix eucalypti on leaves of Eucalyptus sp., Gyrothrix oleae on leaves of Olea capensis subsp. macrocarpa, Harzia metrosideri on leaf litter of Metrosideros sp., Hippopotamyces phragmitis (incl. Hippopotamyces gen. nov.) on leaves of Phragmites australis, Lectera philenopterae on Philenoptera violacea, Leptosillia mayteni on leaves of Maytenus heterophylla, Lithohypha aloicola and Neoplatysporoides aloes on leaves of Aloe sp., Millesimomyces rhoicissi (incl. Millesimomyces gen. nov.) on leaves of Rhoicissus digitata, Neodevriesia strelitziicola on leaf litter of Strelitzia nicolai, Neokirramyces syzygii (incl. Neokirramyces gen. nov.) on leaf spots of Syzygium sp., Nothoramichloridium perseae (incl. Nothoramichloridium gen. nov. and Anungitiomycetaceae fam. nov.) on leaves of Persea americana, Paramycosphaerella watsoniae on leaf spots of Watsonia sp., Penicillium cuddlyae from dog food, Podocarpomyces knysnanus (incl. Podocarpomyces gen. nov.) on leaves of Podocarpus falcatus, Pseudocercospora heteropyxidicola on leaf spots of Heteropyxis natalensis, Pseudopenidiella podocarpi, Scolecobasidium podocarpi and Ceramothyrium podocarpicola on leaves of Podocarpus latifolius, Scolecobasidium blechni on leaves of Blechnum capense, Stomiopeltis syzygii on leaves of Syzygium chordatum, Strelitziomyces knysnanus (incl. Strelitziomyces gen. nov.) on leaves of Strelitzia alba, Talaromyces clemensii from rotting wood in goldmine, Verrucocladosporium visseri on Carpobrotus edulis. Spain, Boletopsis mediterraneensis on soil, Calycina cortegadensisi on a living twig of Castanea sativa, Emmonsiellopsis tuberculata in fluvial sediments, Mollisia cortegadensis on dead attached twig of Quercus robur, Psathyrella ovispora on soil, Pseudobeltrania lauri on leaf litter of Laurus azorica, Terfezia dunensis in soil, Tuber lucentum in soil, Venturia submersa on submerged plant debris. Thailand, Cordyceps jakajanicola on cicada nymph, Cordyceps kuiburiensis on spider, Distoseptispora caricis on leaves of Carex sp., Ophiocordyceps khonkaenensis on cicada nymph. USA, Cytosporella juncicola and Davidiellomyces juncicola on culms of Juncus effusus, Monochaetia massachusettsianum from air sample, Neohelicomyces melaleucae and Periconia neobrittanica on leaves of Melaleuca styphelioides × lanceolata, Pseudocamarosporium eucalypti on leaves of Eucalyptus sp., Pseudogymnoascus lindneri from sediment in a mine, Pseudogymnoascus turneri from sediment in a railroad tunnel, Pulchroboletus sclerotiorum on soil, Zygosporium pseudomasonii on leaf of Serenoa repens. Vietnam, Boletus candidissimus and Veloporphyrellus vulpinus on soil. Morphological and culture characteristics are supported by DNA barcodes.

Androgen and pituitary control of penile nitric oxide synthase and erectile function in the rat

Castration of adult male rats reduces by half the penile erectile response to electrical field stimulation (EFS) of the cavernosal nerve, and the activity of penile nitric oxide synthase (NOS). Both changes are prevented by androgen administration. We have now investigated whether other strategies of androgen ablation or competition may act as stronger inhibitors, and, if so, whether the stronger inhibition is due to the depletion of penile NOS content. Rats were castrated or left intact and were treated daily as follows: 1) intact, with the antiandrogen flutamide (25 mg/kg/day, i.p.); 2) castrated, with similar treatment; 3) castrated, with 17 beta-estradiol 3-benzoate (estradiol; via silastic tubing, s.c.). Additional groups of intact rats received injections of a GnRH antagonist (GnRHA, 1.25 mg/kg, s.c.), or were hypophysectomized and left untreated. Controls were untreated intact and castrated animals. After 7 days, rats were subjected to EFS, and the ratios between maximal intracavernosal pressure (MIP) and mean arterial pressure (MAP) were measured. Penile NOS activity and the contents of neuronal NOS (nNOS) and endothelial NOS (eNOS) were determined. Castration reduced the MIP:MAP ratio and penile NOS activity. Androgen receptor blockade with flutamide induced a similar response in intact rats. When flutamide treatment was combined with castration, the erectile response was nearly abolished, but NOS activity was not decreased below the values in castrated rats. Estradiol given to castrated rats and hypophysectomy or GnRHA treatment in intact rats diminished the erectile response below the level in castrated animals. In hypophysectomized rats, penile NOS activity fell below levels in castrated animals. contents of nNOS and eNOS were not significantly reduced by any treatment. These data suggest that penile erection in the rat is completely dependent on androgens, presumably because of their role in the maintenance of penile NOS activity and of other ancillary factors. However, only the complete blockade of residual androgen effects at the tissue level or a total androgen depletion can abolish the erectile response.

Construction and characterization of a bovine bacterial artificial chromosome library

A bacterial artificial chromosome (BAC) library has been constructed for use in bovine genome mapping using constructed for use in bovine genome mapping using the pBeloBAC11 vector. Currently, the library consists of 23,040 clones, which achieves a 70% probability (P=0.70) of the library containing a specific unique DNA sequence. Sixty thousand clones, or about three haploid bovine genomes, will be required to achieve a 95% probability (P=0.95) of containing a unique sequence. An average insert size of 146 kb was estimated from the analysis of 77 randomly selected BAC clones produced by one or two rounds of size selection. The bovine DNA inserts proved to be very stable for at least 100 cell generations. No chimeric clones were detected among 11 large, size-selected BAC clones using fluorescence in situ hybridization (FISH) on metaphase bovine chromosomes. Thirty-three of 46 (72%) sequences were present in the library in at least one copy, which is consistent with the estimated 70% probability of this library containing a unique DNA sequence. A BAC clone as sequence-tagged sites for genetic mapping. These markers cosegregated, and no recombinants were detected in 193 informative meioses. Plasmid end rescue and the inverse polymerase chain reaction methods were used to rescue both ends of this BAC clone, and chromosome walking was performed using PCR primers designed within the end region sequences. Based on our experimental results, the BAC system provides a very useful tool for complex genome analysis.

Induction of apoptosis in the germ cells of adult male rats after exposure to cyclophosphamide

Treatment with cyclophosphamide, a commonly used anticancer drug, may result in oligozoospermia or azoospermia. The objective of this study was to determine whether exposure of male rats to cyclophosphamide induces apoptosis in male germ cells, and if so, when the peak of apoptosis occurs and at what specific stages of spermatogenesis. The presence of apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) detection in situ and by an increase in DNA fragmentation (DNA ladder). To determine the time course of drug-induced apoptosis, male Sprague-Dawley rats were treated with a single dose (70 mg/kg BW) of cyclophosphamide, and the testes were fixed 0, 4, 8, 12, 18, 24, and 48 h after treatment. To determine the dose response, rats were treated with doses of cyclophosphamide (0, 2, 7, 20, and 70 mg/kg), and the testes were fixed 12 h after treatment. A low spontaneous incidence of apoptosis was observed in controls, in particular in premeiotic germ cells of stages I-IV and XI-XIV of the seminiferous tubules. In cyclophosphamide-exposed rats, the incidence of apoptosis increased progressively at 4 h and 8 h, reached a peak at 12 h (about 3.5-fold above control), and then decreased rapidly to control levels by 48 h. A 70-mg/kg dose of cyclophosphamide induced a significant increase in apoptosis; lower doses did not. Although drug-induced apoptosis occurred in all stages of germ cells, it was most pronounced in spermatogonia and spermatocytes in stages I-IV and XI-XIV. Thus, apoptosis may be involved in the occurrence of oligozoospermia or azoospermia after cyclophosphamide treatment. Apoptosis of damaged premeiotic germ cells may serve a critical role in protecting subsequent generations from the diverse effects of toxicants.

Cold adaptive thermogenesis in small mammals from different geographical zones of China

The mechanisms of thermogenesis and thermoregulation were studied in the tree shrew (Tupaia belangeri) and greater vole (Eothenomys miletus) of the subtropical region, and Brandt's vole (Microtus brandti), Mongolian gerbil (Meriones unguiculatus), Daurian ground squirrel (Spermophilus dauricus) and plateau pika (Ochotona curzoniae) of the northern temperate zone. Resting metabolic rate (RMR) and non-shivering thermogenesis (NST) increased significantly in T. belangeri, E. miletus, M. brandti and M. unguiculatus after cold acclimation (4 degrees C) for 4 weeks. In T. belangeri, the increase in RMR and thermogenesis at liver cellular level were responsible for enhancing the capacity of enduring cold stress, and homeothermia was simultaneously extended. Stable body temperature in M. brandti, E. miletus, M. unguiculatus and O. curzoniae was maintained mainly through increase in NST, brown adipose tissue (BAT) mass and its mitochondrial protein content, and the upregulation of uncoupling protein (UCP1) mRNA, as well as enhancement of the activity of cytochrome C oxidase, alpha-glycerophosphate oxidase and T(4) 5'-deiodinase in BAT mitochondria. The RMR in O. curzoniae and euthermic S. dauricus was not changed, while NST significantly increased during cold exposure; the former maintained their stable body temperature and mass, while body temperature in the latter declined by 4.8 degrees C. The serum T(3) concentration or ratio of T(3)/T(4) in all the species was enhanced after cold acclimation. Results indicated that: (1) the adaptive mechanisms of T. belangeri residing in the subtropical region to cold are primarily by increasing RMR and secondly by increasing NST, and the mechanisms of thermogenesis are similar to those in tropical mammals; (2) in small mammals residing in northern regions, the adaptation to cold is chiefly to increase NST; (3) the mechanism of cold-induced thermogenesis in E. miletus residing in subtropical and high mountain regions is similar to that in the north; (4) a low RMR in warm environments and peak RMR and NST in cold environments enabled M. unguiculatus to tolerate a semi-desert climate; (5) O. curzoniae has unusually high RMR and high NST, acting mainly via increasing NST to adapt to extreme cold of the Qinghai-Tibet Plateau; (6) the adaptation of euthermic S. dauricus to cold is due to an increase in NST and a relaxed homeothermia; and lastly (7) the thyroid hormone is involved in the regulation of cold adaptive thermogenesis in all the species studied.

Cadmium and its epigenetic effects

Cadmium (Cd) is a toxic, nonessential transition metal and contributes a health risk to humans, including various cancers and cardiovascular diseases; however, underlying molecular mechanisms remain largely unknown. Cells transmit information to the next generation via two distinct ways: genetic and epigenetic. Chemical modifications to DNA or histone that alters the structure of chromatin without change of DNA nucleotide sequence are known as epigenetics. These heritable epigenetic changes include DNA methylation, post-translational modifications of histone tails (acetylation, methylation, phosphorylation, etc), and higher order packaging of DNA around nucleosomes. Apart from DNA methyltransferases, histone modification enzymes such as histone acetyltransferase, histone deacetylase, and methyltransferase, and microRNAs (miRNAs) all involve in these epigenetic changes. Recent studies indicate that Cd is able to induce various epigenetic changes in plant and mammalian cells in vitro and in vivo. Since aberrant epigenetics plays a critical role in the development of various cancers and chronic diseases, Cd may cause the above-mentioned pathogenic risks via epigenetic mechanisms. Here we review the in vitro and in vivo evidence of epigenetic effects of Cd. The available findings indicate that epigenetics occurred in association with Cd induction of malignant transformation of cells and pathological proliferation of tissues, suggesting that epigenetic effects may play a role in Cd toxic, particularly carcinogenic effects. The future of environmental epigenomic research on Cd should include the role of epigenetics in determining long-term and late-onset health effects following Cd exposure.

Medical care expenditures for hypertension, its complications, and its comorbidities

OBJECTIVES

Medical expenditures attributed to hypertension were estimated, including expenditures for cardiovascular complications, other conditions for which hypertensives are at higher risk, and comorbidities (secondary diagnoses) that raise the cost of medical care. This article presents total, per capita, and per condition US expenditures in 1998 according to sex, age, and type of health service.

METHODS

A variety of national data sources were used to disaggregate national health expenditures in 1998 by diagnosis. Expenditures for cardiovascular complications and other conditions for which hypertensives had higher rates of utilization were determined by analysis of attributable risks. Additional expenditures generated by extra hospital inpatient days and higher charges for nursing home and home health care for comorbidities were estimated by regression analyses.

RESULTS

In 1998, $108.8 billion in health care spending was attributed to hypertension, 12.6% of total national spending that could be allocated to diagnoses, including $22.8 billion for hypertension, $29.7 billion for cardiovascular complications, and $56.4 billion for other diagnoses. Per capita expenditures increased with age from $249 for those younger than 65 years to $3,007 for those 85 years and older. The average amount spent per hypertensive condition was $3,787. Expenditures were generally higher for females.

CONCLUSIONS

The economic burden of hypertension is large, but health services directly related to hypertension account for only a fraction of attributed expenditures. Comprehensive accounting of expenditures more accurately assesses the cost of hypertension and potential savings from prevention and treatment. Alteration of lifestyles and medical intervention provide opportunities to reduce national health expenditures.

Reduction of penile nitric oxide synthase in diabetic BB/WORdp (type I) and BBZ/WORdp (type II) rats with erectile dysfunction

Erectile dysfunction occurs frequently in human diabetes, and it is sometimes associated with hypogonadism. These conditions also develop in a model of insulin-dependent (type I) diabetes, the BB/WORdp (diabetic prone) rat but have not yet been investigated in the model of insulin-resistant (type II) diabetes, the BBZ/WOR rat. It is also unknown whether diabetes-related impotence is due to reduced levels of the mediator of penile erection, nitric oxide, caused by a decrease of nitric oxide synthase (NOS) in the penis. To clarify these questions, groups (n = 5-6) of diabetic BB/WORdp (insulin-maintained) and BBZ/WOR rats were age-matched with diabetic-resistant BB/WORdr and non-diabetic BB/WORdp rats and submitted to determinations of serum glucose, testosterone, and penile reflexes (cups and flips). Erectile dysfunction was found in all of type I and in most of type II diabetic animals (glycemias of 25.0 and 31.1 mM), at the selected mean ages of 310 and 180 days old, respectively. This was evidenced by over 95% decreases of erectile reflexes in both types of diabetes and was accompanied by 75% reduction of serum testosterone. Soluble NOS activity was measured in penile tissue from the diabetic rats with impaired erectile reflexes and in the corresponding controls, by the (3H)-L-arginine/citrulline conversion assay. The neuronal NOS isoform (nNOS) content was determined by a semiquantitative western blot assay. Both types of diabetes showed a marked decrease of penile NOS activity (74 and 55%, respectively), and a lower reduction of penile nNOS content (47 and 33%, respectively). No endogenous NOS inhibitor was detected in the diabetic type I penile cytosol by cross-mixing NOS activity assays. Our data support a common etiology for erectile dysfunction present in rats with types I and II diabetes mellitus and suggest that the etiology is related to a decrease of penile NOS derived in part from serum androgen deficiency.