bluuebunny/crossref_metadata_2025 huggingface dataset:
Islet-1 Controls the Differentiation of Retinal Bipolar and Cholinergic Amacrine Cells
Authors: Elshatory Yasser , Everhart Drew , Deng Min , Xie Xiaoling , Barlow Robert B. , Gan Lin
Published: November 2007

Whereas the mammalian retina possesses a repertoire of factors known to establish general retinal cell types, these factors alone cannot explain the vast diversity of neuronal subtypes. In other CNS regions, the differentiation of diverse neuronal pools is governed by coordinately acting LIM-homeodomain proteins including the Islet-class factor Islet-1 (Isl1). We report that deletion ofIsl1profoundly disrupts retinal function as assessed by electroretinograms and vision as assessed by optomotor behavior. These deficits are coupled with marked reductions in mature ON- and OFF-bipolar (>76%), cholinergic amacrine (93%), and ganglion (71%) cells. Mosaic deletion of Isl1 permitted a chimeric analysis of “wild-type” cells in a predominantlyIsl1-null environment, demonstrating a cell-autonomous role for Isl1 in rod bipolar and cholinergic amacrine development. Furthermore, the effects on bipolar cell development appear to be dissociable from the preceding retinal ganglion cell loss, becausePou4f2-null mice are devoid of similar defects in bipolar cell marker expression. Expression of the ON- and OFF-bipolar cell differentiation factors Bhlhb4 and Vsx1, respectively, requires the presence of Isl1, whereas the early bipolar cell marker Prox1 initially did not. Thus, Isl1 is required for engaging bipolar differentiation pathways but not for general bipolar cell specification. Spatiotemporal expression analysis of additional LIM-homeobox genes identifies a LIM-homeobox gene network during bipolar cell development that includesLhx3andLhx4. We conclude that Isl1 has an indispensable role in retinal neuron differentiation within restricted cell populations and this function may reflect a broader role for other LIM-homeobox genes in retinal development, and perhaps in establishing neuronal subtypes.
Phosphorylation of the Ca2+-Binding Protein CaBP4 by Protein Kinase C ζ in Photoreceptors
Authors: Lee Amy , Jimenez Amber , Cui Guiying , Haeseleer Françoise
Published: November 2007

CaBP4 is a calmodulin-like neuronal calcium-binding protein that is crucial for the development and/or maintenance of the cone and rod photoreceptor synapse. Previously, we showed that CaBP4 directly regulates Cav1 L-type Ca2+channels, which are essential for normal photoreceptor synaptic transmission. Here, we show that the function of CaBP4 is regulated by phosphorylation. CaBP4 is phosphorylated by protein kinase C ζ (PKCζ) at serine 37 bothin vitroand in the retina and colocalizes with PKCζ in photoreceptors. CaBP4 phosphorylation is greater in light-adapted than dark-adapted mouse retinas. In electrophysiological recordings of cells transfected with Cav1.3 and CaBP4, mutation of the serine 37 to alanine abolished the effect of CaBP4 in prolonging the Ca2+current through Cav1.3 channel, whereas inactivating mutations in the CaBP4 Ca2+-binding sites strengthened Cav1.3 modulation. These findings demonstrate how light-stimulated changes in CaBP4 phosphorylation and Ca2+binding may regulate presynaptic Ca2+signals in photoreceptors.
On-Line Control of Grasping Actions: Object-Specific Motor Facilitation Requires Sustained Visual Input
Authors: Prabhu Gita , Lemon Roger , Haggard Patrick
Published: November 2007

Dorsal stream visual processing is generally considered to underlie visually driven action, but when subjects grasp an object from memory, as visual information is not available, ventral stream characteristics emerge. In this study we use paired-pulse transcranial magnetic stimulation (TMS) to investigate the importance of the current visual input during visuomotor grasp. Previously, the amplitude of the paired-pulse motor evoked potentials (MEPs) in hand muscles before movement onset have been shown to predict the subsequent pattern of muscle activity during grasp. Specific facilitation of paired-pulse MEPs may reflect premotor–motor (PMC–M1) cortex connectivity. Here we investigate the paired-pulse MEPs evoked under memory-cued and visually driven conditions before grasping one of two possible target objects (a handle or a disc). All trials began with a delay period of 1200 ms. Then, a TMS pulse served as the cue to reach, grasp and hold the target object for 0.5 s. Total trial length was 5 s. Both objects were continually visible in both conditions, but the way in which the target object was designated differed between conditions. In the memory-cued condition, the target object was illuminated for the first 200 ms of the trial only. In the visually driven condition, the target object was illuminated throughout the 5 s trial. Thus, the conditions differed in whether or not the object to be grasped was designated at the time of movement initiation. We found that the pattern of paired-pulse MEP facilitation matched the pattern of object-specific muscle activity only for the visually driven condition. The results suggest that PMC–M1 connectivity contributes to action selection only when immediate sensory information specifies which action to make.
Fundamental Failures of Shape Constancy Resulting from Cortical Anisotropy
Authors: Cohen Elias H. , Zaidi Qasim
Published: November 2007

Contrary to the conventional assumption that humans perceive shapes of rigid objects as constant despite retinal-image variations caused by changes in orientation and position, we show that the depths of three-dimensional (3-D) textured shapes appear to vary when the image is rotated. In paired comparisons of static stimuli, depth amplitude was perceived to be greater at vertical than at oblique orientations. A similar oblique bias was found for simple two-dimensional (2-D) obtuse angles. Using projective geometry to link angle magnitude to the orientation flows that convey 3-D shape from texture cues, we show quantitatively that the 2-D bias predicts the 3-D bias. Our finding that perception of angular magnitude is dependent on orientation has broad implications for shape constancy because orientation flows have also been implicated in 3-D perception from reflections and shading, and contour curvature is fundamental to uncovering depth and part-structure of shapes. We examined the roles played in the observed biases by anisotropies in numbers and tuning widths of orientation-tuned cells in striate cortex as well as the distribution of oriented energy in natural scenes. An optimal stimulus decoding model for 2-D angles revealed that the narrower tuning of cells for horizontal orientations combined with cross-orientation inhibition explains the orientation-dependent angle distortion and hence the 3-D shape inconstancy. Variations in properties within neural populations can thus have direct effects on visual perceptions and need to be included in neural decoding models.
The Salami Maker Who Fought the Law
Authors: digregorio sarah
Published: November 2007

Since the early 20th century, the Buzzio family has been making and selling traditional Piedmontese charcuterie and fresh sausages out of an unassuming Manhattan storefront. Marc Buzzio, whose father Ugo founded the business, provides all manner of salamis to famous chefs and neighborhood regulars alike. Buzzio works in small batches, crafting his product out of heritage pork, and curing it in his low-tech drying room, the same way it has been done for centuries.

But in the summer of 2002, disaster struck in the form of new USDA regulations for dry aged, ready-to-eat products. The regulations were written with industrial producers in mind, not mom-and-pop operations, and certainly not this beloved neighborhood store where dry-cured sausages have been made in the same careful way for nearly eighty years. This story chronicles the struggles of a small producer to adapt to regulations that are increasingly designed for mass-market food production.
Asia's First Lady of Coffee
Authors: girish uma
Published: November 2007

Asia's only woman coffee taster, Sunalini Menon, is CEO of Coffee Lab, a Bangalore-based consultancy which boasts of state-of-the-art equipment and offers a gamut of seed-to-the-cup services: coffee evaluation, education, training, certification and advisory services. The lab also assists in the special preparations of coffee such as estate brands and specialty coffees based on plant strain, region of growth, and the intrinsic properties of various beans. Coffee, believes Menon, is a very sensitive living being that emotes. Palate-sensitivity and attention to detail are a good taster's key qualities. A good taster possesses a sharp acuity of taste, concentration, good memory power, descriptive terminology and communication skills. Formulating blends is a vital part of Menon's business. Where and how coffee is grown affects the size, density and flavor of the bean. Coffee has as many notes and flavors as wine and you have to feel it layer by layer, advises Menon. But the mind and palate need a break between tasting sessions——eating a cracker or a piece of bread cleanses the palate. An hour before and after lunch are no-no for tasting sessions as are fatigue and poor health. Alcohol, tobacco and spicy food are to be avoided as well.
Isolation of Malassezia pachydermatis and M. sympodialis from the external ear canal of cats with and without otitis externa
Authors: Dizotti C. , Coutinho Selene
Published: November 2007

The objective of this study was to determine the presence ofMalasseziaspp. in the external ear canal of cats with and without otitis. Forty-five animals were studied, 20 with and 25 without otitis externa (OE). Cerumen or secretion from external ear canal samples was cultured on modified Mycosel agar and sterile olive oil was added to the surface of the medium before specimen seeding. The isolates were analysed for macro- and micromorphology and identified by catalase tests and on the basis of growth on Tween 20, 40, 60 and 80.Malasseziaspp. were isolated from 15 out of 20 (75%) animals with otitis and from 7 out of 25 (28%) cats without OE; the difference between the two groups was statistically significant (P ≤ 0.05).Malassezia pachydermatisandM. sympodialiswere isolated from 60% (12/20) and 40% (8/20) of cats with otitis, respectively, with no significant difference in the frequency of isolation between the two species. In the microflora of the healthy ear canalM. pachydermatiswas significantly more common (6/25, 24%) thanM. sympodialis(1/25, 4%). The present investigation confirms thatM. sympodialiscan also act as an aetiological agent of feline OE, and if commercial veterinary laboratories do not use media with added lipids for the isolation ofMalasseziaspp., this might lead to false-negative results.
Implicit iterative process for common fixed point of a finite family of asymptotically nonexpansive mappings
Authors: Gu Feng
Published: November 2007

The purpose of this paper is to study the weak and strong convergence of implicit iteration process to a common fixed point for a finite family of asymptotically nonexpansive mappings and nonexpansive mappings in Banach spaces. The results presented in this paper extend and improve the corresponding results of [1,2,4–9,11–15].
Every Abelian group is determined by a subgroup lattice
Authors: Breaz Simion , Călugăreanu Grigore
Published: November 2007

We prove that every Abelian group
G
is determined up to an isomorphism by the subgroup lattice of the group ℤ ×
G
and some other similar results.
Saúde e ambiente no Brasil: desenvolvimento, território e iniqüidade social
Authors: Rigotto Raquel Maria , Augusto Lia Giraldo da Silva
Published: November 2007

As autoras apresentam uma abordagem das iniqüidades sócio-ambientais no Brasil, decorrentes do modelo de desenvolvimento, no contexto atual da globalização, e as perspectivas da luta social. A realização histórica da ideologia do desenvolvimento tem implicado em profundas transformações do território, com sérias repercussões sobre a saúde das populações e dos ecossistemas, as quais apenas muito recentemente começam a ser reconhecidas como problemas na agenda social. A tentativa de conciliar soluções para a crise social e a crise ambiental resultou na formulação da proposta de desenvolvimento sustentável - incorporada em alguns novos discursos no campo da saúde coletiva - cuja análise crítica é o ponto de partida deste artigo. O território foi examinado como um operador útil para analisar a expressão da ligação entre saúde, ambiente e desenvolvimento, revelador do paradoxo entre as potencialidades naturais e humanas do Brasil e sua pobreza, espelho da injustiça ambiental e da violação de direitos humanos. Trata-se de um conceito expandido de ordenação territorial, importante para criar a possibilidade de se compreender o contexto de modernização e de possibilidade das populações pobres conquistarem uma vida melhor.
Environmental sustainability and human well-being indicators from the ecosystem perspective in the Middle Paraíba Region, Rio de Janeiro State, Brazil
Authors: Freitas Carlos Machado de , Schütz Gabriel Eduardo , Oliveira Simone Gomes de
Published: November 2007

Population urbanization is a global trend, and socioeconomic activities in urban areas cause changes that affect the environment and human well-being beyond the specific territories, thus connecting urban to non-urban areas and creating city-regions. This article's objective, from an ecosystem perspective, is to gather a set of information on municipalities (counties) belonging to the Middle Paraíba River Valley Region in the State of Rio de Janeiro, Brazil, in order to identify conditions and trends in environmental sustainability and well-being. The conceptual framework adopted here was that of the Millennium Ecosystem Assessment, identifying direct and indirect driving forces that affect human well-being, with health as a component of the latter. We used a set of available public-domain data and information sources on the municipalities, grouped by socioeconomic and environmental conditions and the soundness of institutional structural well-being for sustainability. The indicators used here point to a process of degradation in the ecosystem services that has still not been prevented by the prevailing institutional structure, thus increasing constraints on well-being and the spread of socio-environmental impacts in the middle and long terms.
Compreensões integradas para a vigilância da saúde em ambiente de floresta: o caso da Chapada do Araripe, Ceará, Brasil
Authors: Augusto Lia Giraldo da Silva , Góes Lourdes
Published: November 2007

São apresentados resultados parciais de estudo para elaboração de modelagem de vigilância da saúde de grupos humanos que vivem do extrativismo vegetal na Floresta Nacional da Chapada do Araripe, Ceará, Brasil. Como principais justificativas do estudo tem-se a importância desta Floresta Nacional para a preservação da qualidade da vida na região do semi-árido nordestino e o contexto de vulnerabilidades das florestas brasileiras. A abordagem metodológica é de um processo coletivo de compreensões integradas relacionadas à subjetividade dos sujeitos em face do ambiente produtivo na floresta, incluindo questões de gênero. O estudo apontou resultados diversos, alguns já previsíveis, outros surpreendentes, do ponto de vista da visibilidade de questões presentes no cotidiano das populações que trabalham e vivem da floresta.
Correlation between blood mercury levels in mothers and newborns in Itaituba, Pará State, Brazil
Authors: Santos Elisabeth Oliveira , Jesus Iracina Maura de , Câmara Volney de Magalhães , Brabo Edílson da Silva , Jesus Maria Izabel de , Fayal Kleber Freitas , Asmus Carmen Ildes Rodrigues Fróes
Published: November 2007

This study evaluated transplacental mercury transfer by measuring Hg in blood samples of mothers and newborns (umbilical cord) in hospitals in the municipality (county) of Itaituba, Pará State, Brazil. Epidemiological and mercury exposure data were collected, besides clinical birth data. Mercury tests were performed by cold-vapor atomic absorption spectrophotometry. A total of 1,510 women and an equal number of their newborns participated in the study. Mean blood mercury was 11.53µg/L in mothers and 16.68µg/L in newborns (umbilical cord). The highest Hg levels were in the 31-40-year maternal age group and their newborns, with 14.37µg/L and 21.87µg/L, respectively. However, in all age groups the mean mercury level was higher in newborns than in mothers. There was a strong positive correlation between Hg levels in newborns and mothers (r = 0.8019; p = 0.000), with a significant linear regression model (r = 0.5283; p = 0.000). The results highlight the importance of monitoring pregnant women exposed to mercury as part of public health surveillance.
Expression and thyroid hormone regulation of annexins in the anterior pituitary
Authors: Mittag Jens , Oehr Wiebke , Heuer Heike , Hämäläinen Tuula , Brachvogel Bent , Pöschl Ernst , Bauer Karl
Published: November 2007

Due to their property to bind to phospholipids in a Ca2+-dependent manner, proteins of the annexin superfamily are involved in many membrane-related events and thus in various forms of physiological and pathological processes. We were therefore interested in analyzing the mRNA expression of the annexins in the severely disorganized pituitaries of the athyroid Pax8−/− mice in comparison with that of control animals. In neither condition was mRNA expression of the annexins A3, A7, A8, A9, A11, and A13 detectable. The annexins A2, A4, and A6 were equally expressed in wild-type and Pax8−/− mice. Transcript levels of A1 and A10 were highly increased and those of A5 were significantly decreased in the athyroid mutants compared with controls. Treatment of Pax8−/− mice with physiological doses of thyroxine for 3 days normalized the mRNA expression of A1, A5, and A10 indicating that the expression of these annexins is directly regulated by thyroid hormone (TH). Since A5 exhibits by far the highest transcript levels of all annexins in the pituitary and its regulation by TH could be also confirmed at the protein level, we analyzed the mRNA expression of pituitary hormones in A5−/− mice. In these mutants, only the β-FSH mRNA expression was found to be significantly reduced, while the mRNA expression levels of the other pituitary hormones were not altered. These results support the concept that annexins might serve important albeit redundant functions as modulators of pituitary hormone secretion.
Low expression of insulin signaling molecules impairs glucose uptake in adipocytes after early overnutrition
Authors: Rodrigues Ananda L , De Souza Érica P G , Da Silva Simone V , Rodrigues Dayane S B , Nascimento Aline B , Barja-Fidalgo Christina , De Freitas Marta S
Published: November 2007

Experimental and clinical studies have demonstrated that early postnatal overnutrition represents a risk factor for later obesity and associated metabolic and cardiovascular disturbance. In the present study, we assessed the levels of glucose transporter 4 (GLUT-4), GLUT-1, insulin receptor (IR), IR substrate 1 (IRS-1), phosphatidylinositol 3-kinase (PI3K) and Akt expression, as well as insulin-stimulated glucose transport and Akt activity in adipocytes from adult rats previously raised in small litters (SL). The normal litter (NL) served as control group. We also investigated glycemia, insulinemia, plasma lipid levels, and glucose tolerance. Our data demonstrated that early postnatal overfeeding induced a persistent hyperphagia accompanied by a significant increase in body weight until 90 days of age. The SL group also presented a significant increase (∼42%) in epidydimal fat weight. Blood glucose, plasma insulin, and lipid levels were similar among the animals from the SL and NL groups. While insulin-stimulated glucose uptake was approximately twofold higher in adipocytes from the NL group, no stimulatory effect was observed in the SL group. The impaired insulin-stimulated glucose transport in adipose cells from the SL rats was associated with a significant decrease in GLUT-4, IRS-1 and PI3K expression, and Akt activity. In contrast, IR and Akt expression in adipocytes was not different between the SL and NL groups. Despite these alterations, our results showed no differences in glucose tolerance test in rats raised under different feeding conditions. Our findings reinforce a potent and long-term effect of neonatal overfeeding, which can program major changes in the metabolic regulatory mechanisms.
Human adrenal corticocarcinoma NCI-H295R cells produce more androgens than NCI-H295A cells and differ in 3β-hydroxysteroid dehydrogenase type 2 and 17,20 lyase activities
Authors: Samandari Elika , Kempná Petra , Nuoffer Jean-Marc , Hofer Gaby , Mullis Primus E , Flück Christa E
Published: November 2007

The human adrenal cortex produces mineralocorticoids, glucocorticoids, and androgens in a species-specific, hormonally regulated, zone-specific, and developmentally characteristic fashion. Most molecular studies of adrenal steroidogenesis use human adrenocortical NCI-H295A and NCI-H295R cells as a model because appropriate animal models do not exist. NCI-H295A and NCI-H295R cells originate from the same adrenocortical carcinoma which produced predominantly androgens but also smaller amounts of mineralocorticoids and glucocorticoids. Research data obtained from either NCI-H295A or NCI-H295R cells are generally compared, although for the same experiments no direct comparison between the two cell lines has been performed. Therefore, we compared the steroid profile and the expression pattern of important genes involved in steroidogenesis in both cell lines. We found that steroidogenesis differs profoundly. NCI-H295A cells produce more mineralocorticoids, whereas NCI-H295R cells produce more androgens. Expression of the 3β-hydroxysteroid dehydrogenase (HSD3B2), cytochrome b5, and sulfonyltransferase genes is higher in NCI-H295A cells, whereas expression of the cytochrome P450c17 (CYP17), 21-hydroxylase (CYP21), and P450 oxidoreductase genes does not differ between the cell lines. We found lower 3β-hydroxysteroid dehydrogenase type 2 but higher 17,20-lyase activity in NCI-H295R cells explaining the ‘androgenic’ steroid profile for these cells and resembling the zona reticularis of the human adrenal cortex. Both cell lines were found to express the ACTH receptor at low levels consistent with low stimulation by ACTH. By contrast, both cell lines were readily stimulated by 8Br-cAMP. The angiotensin type 1 receptor was highly expressed in NCI-H295R than NCI-H295A cells and angiotensin II stimulated steroidogenesis in NCI-H295R but not NCI-H295A cells. Our data suggest that comparative studies between NCI-H295A and NCI-H295R cells may help find important regulators of mineralocorticoid or androgen biosynthesis.
Identification of two novel chicken GHRH receptor splice variants: implications for the roles of aspartate 56 in the receptor activation and direct ligand–receptor interaction
Authors: Wang Crystal Ying , Wang Yajun , Kwok Amy Ho Yan , Leung Frederick C
Published: November 2007

In this study, two novel GHRHR receptor splice variants, named chicken GHRHR-v1 (cGHRHR-v1) and cGHRHR-v2 respectively, were identified from chicken pituitary using RT-PCR assay. cGHRHR-v1 is characterized by an N-terminal deletion of 36 amino acid residues, including an aspartate at position 56 (Asp56) conserved in G protein-coupled receptor B-I subfamily. cGHRHR-v2 is a carboxyl-terminal truncated receptor variant with four putative transmembrane domains, which arose from alternative use of a splice acceptor site on intron 8. Using the pGL3-CRE-luciferase reporter system, the functionality of the two variants was examined in Chinese hamster ovary cells. cGHRHR-v1 was shown to be capable of transmitting signal upon agonist stimulation, but cGHRHR-v2 could not. Both GHRH and pituitary adenylate cyclase-activating peptide (PACAP) could activate cGHRHR-v1 at high dosages (GHRH ≥10−8 M; PACAP ≥10−6 M) and GHRH was much more potent than PACAP, suggesting that cGHRHR-v1 is a functional membrane-spanning receptor with an impairment in high-affinity ligand binding, rather than in receptor activation and ligand-binding specificity. This finding also points out the possibility that Asp56 is not a critical determinant for receptor activation and direct ligand–receptor interaction. To substantiate this hypothesis, using site-directed mutagenesis, two receptor mutants with replacement of Asp56 by Ala or Gly were generated. Expectedly, chicken or human GHRH could still activate both receptor mutants with reduced potencies (about 2- to 14-fold less potent). Taken together, our findings not only suggest that cGHRHR variants may play a role in controlling normal pituitary functions, but also support that Asp56 is nonessential for receptor activation and direct ligand–receptor interaction.
Cholesterol sulphate affects production of steroid hormones by reducing steroidogenic acute regulatory protein level in adrenocortical cells
Authors: Sugawara Teruo , Nomura Eiji , Hoshi Nobuhiko
Published: November 2007

Steroidogenic acute regulatory (StAR) protein plays a crucial role in the intramitochondrial movement of cholesterol, where P450 side chain cleavage enzyme resides. Cholesterol sulphate (CS), which is present ubiquitously in mammalian tissues, is not only a precursor of sulphated adrenal steroids but also an inhibitor of cholesterol biosynthesis. This study was designed to examine the biological roles of CS in steroidogenesis in adrenocortical cells. Human adrenocortical carcinoma H295R cells were cultured with various amounts of CS. To evaluate steroid hormone synthesis, pregnenolone production in cells was assayed. The amount of pregnenolone produced by H295R cells in culture medium, to which over 50 μg/ml CS was added, was significantly (P<0.05) decreased compared with that produced by control cells. Western blot analysis was performed to determine StAR protein level using whole cell extracts from cells. StAR protein level decreased when the concentration of CS in the medium was 50 μg/ml, whereas the level of glyceraldehyde-3-phosphate dehydrogenase did not change. To examine the mechanism by which StAR gene expression is controlled, we performed RT-PCR and measured promoter activity in cells transfected with pGL2 StAR reporter constructs. StAR mRNA level and promoter activity were decreased in cells. The decrease in StAR protein level is a result of the low StAR gene expression level. In conclusion, CS affects the production of steroid hormones by reducing StAR protein level in adrenocortical cells.
Neuroendocrine profiling in inherited stress-induced arterial hypertension rat strain with stress-sensitive arterial hypertension
Authors: Markel A L , Redina O E , Gilinsky M A , Dymshits G M , Kalashnikova E V , Khvorostova Yu V , Fedoseeva L A , Jacobson G S
Published: November 2007

The functions of the hypothalamic adrenal cortical and sympathetic adrenal medullary systems were studied in rats with inherited stress-induced arterial hypertension (ISIAH strain). A characteristic feature of the ISIAH strain is an increase in arterial blood pressure measured both under basal conditions and after restraint stress in particular. In the control ISIAH rats, the basal plasma ACTH concentration was slightly lower than that in the normotensive Wistar albino Glaxo (WAG) rats, and no differences were found in plasma corticosterone. However, the 0.5-h restraint stress produced higher activation of the adrenal cortex in the ISIAH rats. Gluco- and mineralocorticoid responses to the blood volume reduction stresses and ACTH and corticosterone responses to social stress were stronger in the ISIAH than in the control WAG rats. An increase in epinephrine content in adrenals in the basal state and enhanced response of the sympathetic adrenal medullary system to handling stress were observed in the ISIAH rats. Restraint stress produced significantly higher expression of genes encoding corticotropin-releasing hormone-mRNA in hypothalamus and proopiomelanocortin-mRNA in pituitary in the ISIAH than in the WAG rats. Restraint stress produced a decrease in glucocorticoid receptor (GR) gene expression (GR-mRNA) in hippocampus in the ISIAH, but not in the WAG rats. A persistent increase in tyrosine hydroxylase-mRNA in adrenals of the ISIAH rats was found. It is concluded that the ISIAH rat strain is an appropriate model of stress-sensitive hypertension with the predominant involvement of the hypothalamic adrenal cortical and sympathetic adrenal medullary systems in its pathogenesis.
Evidence for the existence of a local activin–follistatin negative feedback loop in the goldfish pituitary and its regulation by activin and gonadal steroids
Authors: Cheng Gheorghe F Y , Yuen Chi-Wai , Ge Wei
Published: November 2007

Activin is an important regulator of gonadotropin expression and production in the vertebrate pituitary, and its activity is fine-tuned by its binding protein follistatin. In the present study, a full-length cDNA for follistatin was cloned in the goldfish, which shows 74% amino acid sequence identity with that of mammals. Recombinant goldfish follistatin expressed in the Chinese hamster ovary cells significantly blocked activin-induced F5-5 cell differentiation. Goldfish follistatin is expressed in a wide range of tissues including the brain, pituitary, ovary, and testis. The expression of follistatin mRNA in the pituitary is regulated by both activin and gonadal steroids in vitro. Treatment with goldfish activin B for 48 h significantly up-regulated follistatin expression in cultured pituitary cells, suggesting a closed activin–follistatin feedback loop in the pituitary. In agreement with this, both human and goldfish follistatin down-regulated the expression of follistatin itself, probably due to the neutralization of endogenous activin. Examination of FSHβ and LHβ expression in the same samples supports the role of activin and follistatin in the differential regulation of FSH and LH as demonstrated previously. Since the expression level of activin βB in the pituitary is rather stable both in vitro and in vivo, it is conceivable that follistatin may play a pivotal regulatory role in the intra-pituitary activin system. Both estradiol and testosterone up-regulated follistatin expression in vitro, suggesting a mediating role for follistatin in steroid feedback on pituitary hormones. These results provide clues to the potential physiological roles of activin–follistatin system in the regulation of gonadotropin biosynthesis in teleosts.
Ethinylestradiol differentially interferes with IGF-I in liver and extrahepatic sites during development of male and female bony fish
Authors: Shved Natallia , Berishvili Giorgi , D'Cotta Helena , Baroiller Jean-François , Segner Helmut , Eppler Elisabeth , Reinecke Manfred
Published: November 2007

Growth and sexual development are closely interlinked in fish; however, no reports exist on potential effects of estrogen on the GH/IGF-I-axis in developing fish. We investigate whether estrogen exposure during early development affects growth and the IGF-I system, both at the systemic and tissue level. Tilapia were fed from 10 to 40 days post fertilization (DPF) with 17α-ethinylestradiol (EE2). At 50, 75, 90, and 165 DPF, length, weight, sex ratio, serum IGF-I (RIA), pituitary GH mRNA and IGF-I, and estrogen receptor α (ERα) mRNA in liver, gonads, brain, and gills (real-time PCR) were determined and the results correlated to those of in situ hybridization for IGF-I. Developmental exposure to EE2 had persistent effects on sex ratio and growth. Serum IGF-I, hepatic IGF-I mRNA, and the number of IGF-I mRNA-containing hepatocytes were significantly decreased at 75 DPF, while liver ERα mRNA was significantly induced. At 75 DPF, a transient decline of IGF-I mRNA and a largely reduced number of IGF-I mRNA-containing neurons were observed in the female brain. In both sexes, pituitary GH mRNA was significantly suppressed. A transient downregulation of IGF-I mRNA occurred in ovaries (75 DPF) and testes (90 DPF). In agreement, in situ hybridization revealed less IGF-I mRNA signals in granulosa and germ cells. Our results show for the first time that developmental estrogen treatment impairs GH/IGF-I expression in fish, and that the effects persist. These long-lasting effects both seem to be exerted indirectly via inhibition of pituitary GH and directly by suppression of local IGF-I in organ-specific cells.
The effects of targeted deletion of the aromatase enzyme on prostatic contractile responses to noradrenaline in mice
Authors: Gray Katherine T , Short Jennifer L , Simpson Evan R , Ventura Sabatino
Published: November 2007

This investigation aimed to see whether a change in the oestrogen to androgen ratio alters prostate contractility. Isolated organ bath studies using prostates from aromatase knockout (ArKO) mice which were homozygous (ArKO−/−) and heterozygous (ArKO+/−) for the disrupted aromatase cyp19 gene and wild-type littermates (ArKO+/+) were conducted. The distribution of noradrenergic nerves was visualized using the sucrose–potassium phosphate–glyoxylic acid method. ArKO−/− mice had increased prostate weights compared with ArKO+/+ mice. Frequency–response curves to electrical field stimulation (EFS; 0.5 ms pulse duration, 60 V, 0.1–20 Hz) yielded frequency-dependent contractions, while noradrenaline (10 nM–1 mM) and tyramine (1 μM–1 mM) produced concentration-dependent contractions. Prazosin (0.3 μM) attenuated the responses induced by noradrenaline and EFS in all mice (P≤0.019, n=5–7), while cocaine (10 μM) attenuated the responses evoked by tyramine (P<0.001, n=6). There were no genotype differences in EFS- and noradrenaline-induced responses (P≥0.506, n=10–13). Prostates from ArKO−/− and ArKO+/− mice were more sensitive to tyramine than prostates from ArKO+/+ mice (P<0.001, n=11–13). Dense adrenergic innervation of the prostate was similar in all mice. These results suggest that although the absence of aromatase increases prostatic growth, this translates only to a subtle and selective increase in contractility in mature mice.
Evidence for the presence of stem cell-like progenitor cells in human adult pancreas
Authors: Zhao Min , Amiel Stephanie A , Christie Michael R , Muiesan Paolo , Srinivasan Parthi , Littlejohn Wendy , Rela Mohamed , Arno Matthew , Heaton Nigel , Huang Guo Cai
Published: November 2007

The origin of cells replacing ageing β-cells in adult life is unknown. This study assessed the expression of classic stem cell markers: Oct4, Sox2 and CD34 in islet-enriched fractions versus exocrine cell-enriched fractions from 25 adult human pancreases following human islet isolation. Expression of Oct4, Sox2 and CD34 mRNAs was found in all cell samples, with no significant differences between endocrine and exocrine cell fractions. Immunohistochemical staining for Oct4, Sox2, CD133, CD34, CK19, insulin and nestin on human pancreas sections showed that the majority of Oct4+ve cells were found in the walls of small ducts. Similar localisations were observed for Sox2+ve cells. The majority of Sox2+ve cells were found to co-express Oct4 proteins, but not vice versa. Cells positive for Oct4 and Sox2 appeared to be a unique cell population in the adult human pancreases without co-expression for CK19, CD34, CD133, insulin and nestin proteins. The numbers of Oct4+ve and Sox2+ve cells varied among donors and were ∼1–200 and 1–30 per 100 000 pancreatic cells respectively.
The hepatocyte growth factor system as a regulator of female and male gonadal function
Authors: Zachow Rob , Uzumcu Mehmet
Published: November 2007

The hepatocyte growth factor (HGF) system comprises HGF, its receptor (the c-met tyrosine kinase), HGF activator (HGFA) protein, and HGFA inhibitor (HAI). The components of the HGF system have been identified in a plethora of tissues to include the ovary and testis. In its traditional context, the HGF system works via paracrine- and autocrine-mediated feedback in which HGF (of mesenchymal origin) binds and activates c-met (within epithelial cells); target cells then respond to HGF via any number of morphogenic and functional changes. The concomitant presence of HGFA and HAI suggests that HGF bioactivity can be locally modulated. A number of studies have collectively shown that the mammalian ovary and testis contain HGF, c-met, and HGFA; very little is currently known regarding HAI within the gonad. Within the ovary, HGF controls numerous key functions which collectively regulate the growth and differentiation of ovarian follicles; these include cell growth, steroidogenesis, and apoptosis within theca cells and/or granulosa cells. Comparatively, less is known about the function of HGF within the testicular Leydig and Sertoli cells, but evidence is emerging that HGF may regulate somatic cell function, including Leydig cell steroidogenesis. Changes in the cellular origin of HGF and c-met during fetal and postnatal testicular development suggest that HGF, in collaboration with other growth factors, may regulate important aspects of testicular cell morphogenesis and differentiation which enable male sexual viability. Likewise, experimental evidence showing that HGF can modulate many vital processes which enable ovarian follicle growth, differentiation, and function indicate the importance of HGF in female reproduction. This review presents what is currently known regarding the expression of the HGF system and its function within the ovary and testis.
Mind the Gap(s): Discourses and Discontinuity in Digital Literacies
Authors: Merchant Guy
Published: November 2007

Meaning making in new media is rapidly presenting new opportunities and new challenges for those working in formal and informal educational contexts. This article provides an overview of current theory, thinking and commentary in order to map the field of digital literacy and to identify key questions for research and policy development. It identifies some of the discontinuities or gaps that exist between teachers, their students, and what technology can now deliver. Through two case studies the author tells the story of social practices that illustrate everyday digital lives and show how interactions involve a constellation of literacy events. This approach allows him to raise questions about the transfer of such practices into educational contexts and to explore the gaps between informal uses of digital literacy and current classroom literacy routines.
Fragments to Fractals: The Subjunctive Spaces of E-Literature
Authors: Luce-Kapler Rebecca
Published: November 2007

This article chronicles the experience of two writers working in digital technologies to write fiction. One writer, the author of the article, describes how her experience writing with the software Storyspace influenced her writing of print fiction, changing her processes and challenging her notions of genre. The other writer, a 16-year-old secondary student, also wrote with Storyspace. While she did not find the form as challenging as the first writer, she followed similar processes of creation. The author compares the possibilities of digital and print text writing and suggests that there are different potentials. She also suggests that moving from a metaphor of fragments to fractals when thinking of hypertext writing may be a productive way to consider digital literary work.
Massively Multiplayer Online Gaming as a Constellation of Literacy Practices
Authors: Steinkuehler Constance
Published: November 2007

The claim that video games are replacing literacy activities that is bandied about in the American mainstream press is based not only on unspecified definitions of both ‘games' and ‘literacy’ but also on a surprising lack of research on what children actually do when they play video games. In this article, the author examines some of the practices that comprise game play in the context of one genre of video games in particular — massively multiplayer online games (MMOGs). Based on data culled from a two-year online cognitive ethnography of the MMOG Lineage (both I and II), the author argues that forms of video game play such as those entailed in MMOGs are not replacing literacy activities but rather are literacy activities. In order to make this argument, the author surveys the literacy practices that MMOGamers routinely participate in, both within the game's virtual world (e.g. social interaction, in-game letters) and beyond (e.g. online game forums, the creation of fan sites and fan fiction). Then, with this argument in place, she attempts to historicize this popular contempt toward electronic ‘pop culture’ media such as video games and suggest a potentially more productive (and accurate) framing of the literacy practices of today's generation of adolescents and young adults.
Assessment and New Literacies
Authors: Hammett Roberta F.
Published: November 2007

This article argues that if multimodal and new literacies are to become common practices in schools, they have to be included in both school and provincial/state large-scale assessment programmes. Building on current criterion-referenced testing in Newfoundland and Labrador which assesses a range of literacies (viewing, reading, writing, representing, speaking and listening), the article suggests criteria which might be considered in developing holistic and analytic rubrics for assessing new literacies in ways that are productive for learners. The article describes an interactive website that may be used to familiarize teachers and education students with rubrics for assessing children's written and graphic responses to linguistic, graphic and spoken texts.
Teaching Writing in Five Canadian Provinces: A New Literacies Analysis
Authors: Peterson Shelley Stagg , McClay Jill Kedersha
Published: November 2007

This article presents the results of the initial stage of research on grades 4–8 teachers' writing instruction within rural and urban contexts across Canada. Teachers' goals and their use of digital technologies and multimedia are examined within rural and urban schools in five eastern provinces. Through half-hour telephone interviews with 54 teachers, the authors found that perceptions of the value of writing within their communities and the kinds of support for writing that students were given outside school divided along teachers' perceptions of students' social class lines. Language spoken in students' homes also influenced teachers' goals for their students. Only 5 of the 54 teachers interviewed provide opportunities for students to compose on computers. In most teachers' classrooms, computers were used for retyping drafts, and often used at home, to create ‘good copies' that students handed in for grades.
Learning about War and Peace in the Great Lakes Region of Africa
Authors: Bird Lyndsay
Published: November 2007

Two-thirds of the world's conflicts are in Africa. In particular, the Great Lakes region (Rwanda, Burundi, Democratic Republic of Congo, Uganda and Tanzania) continues to see conflicts that are complex, extreme and seemingly intractable. By exploring the narrative experiences of those most affected by the conflicts in the region – specifically refugees from Burundi, the Democratic Republic of Congo and Rwanda living in camps in north-western Tanzania – this article examines to what extent educative processes (holistic formal and informal learning processes) affect people's experience and engagement in violent conflict. The article draws on the author's research that identified different information circuits by which people learned about conflict. In opposition to the common perception that formal schooling effects change, the findings indicated that the primary mechanisms were oral/aural, such as gossip, traditional storytelling and radio. Individual and collective identities were constructed through this process and the research identified how identities could be shifted through different formal and informal educative processes – often through indoctrination or coercion. This article concludes with an indication of alternative strategies for conflict prevention and peacebuilding (particularly within a refugee or similar context). Efforts at peacebuilding continue to falter in the region and this illustrates the need to construct a more inclusive peacemaking process, taking into account the insights and values of those most affected.
Framing Youth within the Politics of Foreign Assistance
Authors: Ignatowski Clare A.
Published: November 2007

Although in the past the field of youth development has been subsumed within or occluded by other traditional development sectors such as education, a re-emerging emphasis on security in US government foreign assistance has tended to foreground youth as a frame of reference for international development programming and public diplomacy. While youth as security threat is by itself a reductive formulation, there are opportunities to grasp more deeply the power of young cohorts to affect social change in multidimensional ways. This article examines how youth issues have been framed within broader policy and program priorities of the United States Agency for International Development (USAID), especially in post-conflict/fragile states, in an effort to illuminate some key dilemmas and knowledge gaps.
Education and Instability: Avoiding the Policy-Practice Gap in an Emerging Field
Authors: Karpińska Z.E. , Yarrow Rachel , Gough L.M.A.
Published: November 2007

The imperative to provide education for communities affected by man-made or natural disaster has been strongly articulated. Since the mid 1990s, a growing body of literature and research has emerged in the fledgling field of ‘education and instability’; however, there is still a pressing need for high-quality, applicable research. The article argues that a scholarly attention to the insights and questions of ‘education and instability’ that privileges practitioner involvement may deepen and add rigour to existing insights. Such research may also raise questions and create critical discussion concerning assumptions about conflict, emergency, aid, policy, participation and service provision, and other issues in education and instability. A budding scholarly community at the University of Oxford is the Conflict and Education Research Group (CERG), comprising researchers who have practical experience of working with development agencies and in crisis situations. The group studies what role there might be for education, broadly defined, in promoting stability, peace and development. The article outlines the CERG's emerging research agenda along with its commitment to moving beyond the policy–practice divide to produce meaningful scholarly research with applicable findings and clear dissemination strategies.
Educational Transfer in Situations Affected by Conflict: Towards a Common Research Endeavour
Authors: Rappleye Jeremy , Paulson Julia
Published: November 2007

This article argues that the field of education and conflict is, in many ways, ‘stuck in its emergence’ because it has yet to develop common theoretical understandings, useful analytical tools, and shared conceptual frameworks to unify and sustain a mutual endeavour by scholars working on a diverse range of topics and cases. In a curious, tentative and collaborative way, therefore, this article seeks to explore potential solutions to this problem by searching for common ground between the fields of education and conflict and educational transfer. Its foremost question is: to what degree can analytical tools recently developed by those interested in policy transfer illuminate the investigations of those interested in education and conflict? To explore this question, two young scholars, one primarily engaged in research into processes of educational transfer and one focused on the dynamics of education and conflict, come together to argue first for the potential of collaboration between the subfields. The article then introduces a series of transfer models and presents examples wherein those models may be useful for the study of education and conflict. Finally, aspects of these models are combined with work done by scholars interested in conflict and transition to present a new conceptual device: ‘Educational Transfer in Situations Affected by Conflict’. The purpose of presenting the new model herein is to elicit critique and feedback from researchers, policy makers and practitioners that, it is hoped, will lead to its further refinement and to an understanding of its potential for establishing common ground.