bluuebunny/crossref_metadata_2025 huggingface dataset:
Connectance of Brazilian social bee: food plant networks is influenced by habitat, but not by latitude, altitude or network size
Authors: Biesmeijer Jacobus C. , Slaa E. Judith , Castro Marina Siqueira de , Viana Blandina Felipe , Kleinert Astrid de M. P. , Imperatriz-Fonseca Vera L.
Published: August 2006

Several recent studies suggest that the level of generalization (measured as percentage connectance) of plant-pollinator networks has several ecological correlates, e.g. latitude and altitude. Here we report on levels of generalization in 27 two-mode networks of social bees and their food plants in various Brazilian habitats and urban environments. Social bees are generalist foragers and are among the most abundant flower visitors in Brazil. They probably account for 30-50% of all plant - flower visitor interactions. Connectance was significantly influenced by habitat. Cerrado forests showed lower connectance than the dry dune habitats, with Atlantic rain forest and urban sites taking intermediate position and arid Caatinga being similar to dunes. This shows that generalization in a plant - flower visitor community can be influenced by habitat even within a group of generalist flower visitors, in our case social bees. We show that the strength of the interactions is not different between Cerrado and semi-arid habitats (dunes and Caatinga) and discuss other explanations for our findings.
[NO TITLE AVAILABLE]
Authors: Zuanon Jansen , Sazima Ivan
Published: August 2006

The trichomycterid catfishes known as candirus are renowned for their blood feeding, but information on their habits under natural conditions is very fragmentary and generally restricted to hosts or habitats. We recorded an undescribed species of the vandelliine genus Paracanthopoma riding the giant jau catfish, Zungaro zungaro (Pimelodidae), in the upper Amazon. The candirus were found on the host's caudal and pectoral fins, as well as the base of the dorsal fin, with their snouts buried up to the eyes in the tough skin of the catfish host. All of them had small amounts of partly digested blood in the distal part of the gut. Along the host's dorsal fin base we found a few additional tiny holes, most of them healed. We suggest that Paracanthopoma feeds on the gill chamber of its hosts, and that the individuals we found were taking a ride partly buried into the host's skin. Our assumption seems supported by the widespread behaviour of vandelliine candirus taking blood from the gill region of their hosts, and by a report of Paracanthopoma parva found on the gills of another species of giant catfish, Brachyplatystoma vaillanti. Additionally, the Paracanthopoma sp. individuals we examined were not gorged with blood as usual for several vandelliines. Species within the genus Paracanthopoma have the longest and most robust snout, and the longest and strongest dentary teeth among blood-feeding candirus, which fit their drilling needs. Taking a ride on a giant host would be advantageous for Paracanthopoma candirus for several reasons: 1) dispersal; 2) no need to search for hosts to feed; and 3) protection from predators. The alternative explanation that Paracanthopoma takes blood from the tiny holes it drills in the skin seems unlikely, due to the recent finding that species of the genus Vandellia are unable to take blood from their hosts actively and cut open a major branchial artery to gorge themselves with blood due to the host's arterial pressure instead. The body parts of the host the Paracanthopoma sp. individuals were attached on have no large vessels that would supply them with plenty of blood. Thus, drilling a hole on a giant host skin seems to serve mostly to anchor the Paracanthopoma candirus to their long-distance cruising catfish host. If our assumption holds true, then species of this genus exemplify an instance of phoresis (hitch-hiking) among the blood-feeding candirus.
Little dragons prefer flowers to maidens: a lizard that laps nectar and pollinates trees
Authors: Sazima Ivan , Sazima Cristina , Sazima Marlies
Published: August 2006

Lizards rarely visit and pollinate flowers, the few recent records being mostly restricted to island habitats. We report here on the Noronha skink (Euprepis atlanticus) seeking nectar in the flowers of the leguminous mulungu tree (Erythrina velutina) at Fernando de Noronha Archipelago, off northeast Brazil. The mulungu tree blooms during the dry season, and each flower secretes copious and diluted nectar throughout the day. The Noronha skink climbs up to the inflorescences and laps the nectar accumulated in the flowers' base. While exploiting the flowers and crawling over the inflorescences, the body parts of the skink contact the anthers and stigmas and pollen adheres to the lizard's scales. The lizard visits inflorescences from the same and different trees, which renders it a potential pollinator. As the mulungu tree blooms during the dry season and the island has little or no natural freshwater supply during drought periods, we suggest that the Noronha skink seeks flower nectar both for its energetic, diluted sugars and the water content.
Gestão do paradoxo "passado versus futuro": uma visão transformacional da gestão de pessoas
Authors: Vasconcelos Isabella Freitas Gouveia de , Mascarenhas André Ofenhejm , Vasconcelos Flávio Carvalho de
Published: August 2006

Este artigo contribui para as discussões sobre o papel da gestão de pessoas nos processos de mudança organizacional, mostrando como a adoção de determinadas orientações podem diminuir os efeitos da polarização perceptiva entre o passado e o futuro que é uma das causas dos fenômenos de resistência à mudança e estresse nos processos de mudança organizacional. Para isso, associam-se as temáticas da administração das mudanças organizacionais e da gestão de pessoas, analisadas em uma perspectiva dialética da evolução. Discute-se o paradoxo entre as dimensões "passado" e "futuro" nas organizações e os seus efeitos no que se refere à gestão das mudanças. Analisa-se um estudo de caso com o objetivo de avançar a discussão do modelo transformacional de gestão de pessoas, mostrando como os efeitos do paradoxo "passado versus futuro" foram evitados em uma organização que implementou mudanças por meio de estratégias adaptativas por meio das quais os indivíduos puderam utilizar os meios de ação e cognição desenvolvidos na estrutura organizacional anterior para se identificar e se engajar em um novo projeto de organização.
Metabolism of alkaloids in coffee plants
Authors: Ashihara Hiroshi
Published: August 2006

Coffee beans contain two types of alkaloids, caffeine and trigonelline, as major components. This review describes the distribution and metabolism of these compounds. Caffeine is synthesised from xanthosine derived from purine nucleotides. The major biosynthetic route is xanthosine -> 7-methylxanthosine -> 7-methylxanthine -> theobromine -> caffeine. Degradation activity of caffeine in coffee plants is very low, but catabolism of theophylline is always present. Theophylline is converted to xanthine, and then enters the conventional purine degradation pathway. A recent development in caffeine research is the successful cloning of genes of N-methyltransferases and characterization of recombinant proteins of these genes. Possible biotechnological applications are discussed briefly. Trigonelline (N-methylnicotinic acid) is synthesised from nicotinic acid derived from nicotinamide adenine nucleotides. Nicotinate N-methyltransferase (trigonelline synthase) activity was detected in coffee plants, but purification of this enzyme or cloning of the genes of this N-methyltransferase has not yet been reported. The degradation activity of trigonelline in coffee plants is extremely low.
Coffee seed physiology
Authors: Eira Mirian T. S. , Silva E. A. Amaral da , De Castro Renato D. , Dussert Stéphane , Walters Christina , Bewley J. Derek , Hilhorst Henk W. M.
Published: August 2006

Considerable advances in our understanding of coffee seed physiology have been made in recent years. However, despite intense research efforts, there are many aspects that remain unclear. This paper gives an overview of the current understanding of the more important features concerning coffee seed physiology, and provides information on recent findings on seed development, germination, storage and longevity.
The lipid fraction of the coffee bean
Authors: Speer Karl , Kölling-Speer Isabelle
Published: August 2006

The lipid fraction of coffee is composed mainly of triacylglycerols, sterols and tocopherols, the typical components found in all common edible vegetable oils. Additionally, the so-called coffee oil contains diterpenes of the kaurene family in proportions of up to 20 % of the total lipids. Diterpenes are of interest because of their analytical and physiological effects. The composition of the main lipid components of the two most important coffee species, Coffea arabica and Coffea canphora var. Robusta is presented. In addition, the influences of typical processes like roasting and steaming on selected lipid components as well as the effects of the storage of green coffee beans under different conditions will be described. Furthermore, new findings regarding the 5-hydroxytryptamides, the main parts of the coffee wax located on the outer layer of the bean and the recently identified components coffeadiol and arabiol I will also be discussed.
Aterogênese em artéria ilíaca comum de suínos submetidos à homocisteinemia induzida pela ingestão de metionina
Authors: França Luís Henrique Gil , Pereira Adamastor Humberto , Perini Sílvio César , Aveline Celso Curcio , Argenta Rodrigo , Mollerke Roseli de Oliveira , Soares Marcos Eugenio , Nóbrega Fernanda , Ferreira Márcio Poletto
Published: August 2006

OBJETIVO: Avaliar os efeitos da homocisteinemia induzida na artéria ilíaca de suínos. MATERIAL E MÉTODO: Realizou-se estudo experimental comparativo em dois grupos homogêneos de sete suínos da raça Macau, com peso entre 20 e 30 kg durante 30 dias. Os animais foram divididos em dois grupos, sendo um deles alimentado com metionina adicionada à dieta por um período de 4 semanas. Foram colhidas amostras de sangue para a dosagem de colesterol, triglicerídeos, HDL e homocisteína. Os animais foram submetidos à arteriografia para avaliação da perviedade das artérias ilíacas e, posteriormente, sacrificados. As artérias ilíacas foram enviadas para análise histológica. RESULTADOS: Os animais sobreviveram ao experimento, e não houve alterações significativas nos níveis de colesterol total, triglicerídeos e HDL nos dois grupos. O exame microscópico do grupo-controle não apresentou alterações patológicas e foi semelhante em todas as preparações examinadas. No grupo da dieta com metionina, as placas eram formadas por macrófagos espumosos, mas não foram observadas células musculares lisas, cristais de colesterol ou células inflamatórias. A túnica média apresentava-se com lâmina elástica interna íntegra. No grupo-controle, não houve alteração nos níveis de homocisteína durante o experimento. No grupo-metionina, houve aumento dos níveis séricos da homocisteína, com valor médio de 59,80 µmol/l após 30 dias de dieta rica em metionina. CONCLUSÃO: A homocisteinemia induzida pela metionina causa aterogênese nas artérias ilíacas de suínos.
Estenose carotídea acima de 70% em pacientes no pré-operatório de cirurgia da aorta abdominal: freqüência e fatores de risco
Authors: Ferreira André Ventura , Santos Vanessa Prado dos , Caffaro Roberto Augusto
Published: August 2006

OBJETIVO: Analisar a freqüência e os fatores de risco associados à estenose carotídea acima de 70% em pacientes que serão submetidos a cirurgias de aorta abdominal. MATERIAL E MÉTODO: Foram analisados 94 pacientes que realizaram ultra-som Doppler de carótidas no pré-operatório de cirurgias de aorta abdominal entre janeiro de 2000 e janeiro de 2003, pela disciplina de Cirurgia Vascular da Santa Casa de São Paulo. RESULTADOS: Sessenta e sete pacientes (71%) eram homens. Dentre os 94 pacientes, 42 (44,6%) tinham doença oclusiva aorto-ilíaca, e 52 (53,4%), aneurismas da aorta abdominal (AAA). A análise dos dados mostrou uma prevalência de estenose de carótidas acima de 70% em 8,33% dos pacientes com AAA e em 13,51% dos pacientes com doença oclusiva aorto-ilíaca, diferença esta sem significância estatística (P = 0,5). Nos pacientes que apresentavam antecedente de isquemia cerebral - acidente vascular cerebral (AVC) ou ataque isquêmico transitório (AIT) -, houve uma prevalência estatisticamente maior de estenose carotídea entre 70 e 99%. Outros fatores de risco para aterosclerose, como sexo masculino, diabetes, hipertensão arterial e tabagismo, não foram preditivos da presença de estenose carotídea acima de 70%. CONCLUSÃO: A freqüência de estenose da carótida acima de 70% em pacientes no pré-operatório de cirurgia de aorta foi de 9,57%, e a presença de antecedente de AVC ou AIT na história foi preditiva de estenose acima de 70% neste grupo de pacientes.
Avaliação prognóstica precoce da asma aguda na sala de emergência
Authors: Piovesan Deise Marcela , Menegotto Diego Milan , Kang Suzie , Franciscatto Eduardo , Millan Thaís , Hoffmann Cristine , Pasin Lílian Rech , Fischer Josiane , Barreto Sérgio Saldanha Menna , Dalcin Paulo de Tarso Roth
Published: August 2006

OBJETIVO: Estudar medidas clínicas e funcionais pulmonares utilizadas nos primeiros quinze minutos de manejo da asma aguda em um serviço de emergência, para predição prognóstica. MÉTODOS: Estudo de coorte, prospectivo, que incluiu pacientes consecutivos com asma aguda, com idades entre doze e 55 anos e medida do pico de fluxo expiratório menor ou igual a 50% do previsto. Realizaram-se avaliações na admissão, aos quinze minutos e em quatro horas após o início do tratamento. O tratamento incluiu salbutamol e ipratrópio, administrados por aerossol dosimetrado com espaçador, e 100 mg de hidrocortisona intravenosa. O desfecho favorável foi definido pelo pico de fluxo expiratório maior ou igual a 50% do previsto após a quarta hora de tratamento, e o desfecho desfavorável pelo pico de fluxo expiratório menor que 50% do previsto. RESULTADOS: Tiveram desfecho favorável 27 pacientes e desfavorável 24. A análise multivariada identificou o pico de fluxo expiratório em porcentagem do previsto aos quinze minutos como variável mais preditiva. O pico de fluxo expiratório maior ou igual a 40% aos quinze minutos mostrou significativa contribuição em predizer desfecho favorável (sensibilidade = 0,74, especificidade = 1,00 e valor preditivo positivo = 1,00). O pico de fluxo expiratório menor que 30% aos quinze minutos contribuiu para predizer desfecho desfavorável (sensibilidade = 0,54, especificidade = 0,93 e valor preditivo positivo = 0,87). CONCLUSÃO: O estudo sugeriu que a medida do pico de fluxo expiratório aos quinze minutos do manejo da asma aguda em um serviço de emergência é um instrumento útil para avaliação prognóstica.
Incidência de lesão pulmonar aguda e síndrome da angústia respiratória aguda no centro de tratamento intensivo de um hospital universitário: um estudo prospectivo
Authors: Oliveira Raquel Hermes Rosa , Basille Filho Aníbal
Published: August 2006

OBJETIVO: Estabelecer a incidência de lesão pulmonar aguda e síndrome da angústia respiratória aguda, os principais fatores de risco associados e a mortalidade em um centro de tratamento intensivo. Comparar os pacientes que desenvolveram lesão pulmonar com pacientes com fatores de risco, porém sem lesão pulmonar aguda e síndrome da angústia respiratória aguda. MÉTODOS: O estudo foi realizado no centro de tratamento intensivo da Unidade de Emergência do Hospital das Clínicas de Ribeirão Preto. Os pacientes admitidos no período de maio de 2001 a abril de 2002 foram acompanhados prospectivamente. Foram registrados: características clínicas, índice Acute Physiologic and Chronic Health Evaluation II, complicações, tempo de internação no centro de tratamento intensivo e no hospital, e dados sobre a lesão pulmonar. RESULTADOS: ocorreram 524 admissões no período, 175 pacientes apresentaram fatores de risco para lesão pulmonar aguda e síndrome da angústia respiratória aguda (33,4%), 33 desenvolveram síndrome da angústia respiratória aguda (6,3%) e 12 desenvolveram lesão pulmonar aguda (2,3%). Os principais fatores de risco foram pneumonia (37,7%), choque (32,0%), politrauma (24,6%) e sepse (21,1%). Os pacientes que desenvolveram lesão pulmonar aguda tiveram maior índice Acute Physiologic and Chronic Health Evaluation II (p < 0.05), maior freqüência de sepse (p = 0.001), mais complicações (p = 0.001), maior mortalidade (p = 0.001). A principal causa de morte foi a Síndrome de Disfunção de Múltiplos Órgãos e Sistemas (38,5%). CONCLUSÃO: A incidência de LPA e SARA foi de 2,3 e 6,3% respectivamente. Os principais fatores derisco foram pneumonia, choque, politrauma e sepse. Os pacientes com LPA e SARA apresentaram-se mais graves e tiveram alta mortalidade
Perfil funcional de pacientes portadores de seqüela de tuberculose de um hospital universitário
Authors: Ramos Lucia Maria Macedo , Sulmonett Nara , Ferreira Cid Sergio , Henriques Juliana Fulgêncio , Miranda Silvana Spíndola de
Published: August 2006

OBJETIVO: Descrever os dados de função pulmonar de pacientes com seqüela de tuberculose pulmonar, pleural e pleuropulmonar. MÉTODOS: Em um ambulatório de tuberculose de um hospital universitário, de 218 pacientes atendidos, 56 tinham seqüela de tuberculose pulmonar, pleural e pleuropulmonar, e 162 tiveram outros tipos de tuberculose. No laboratório de função pulmonar, 43 foram elegíveis para o estudo, de fevereiro de 2000 a julho de 2004. Foram excluídos os pacientes com doenças prévias, como: asma; doença pulmonar obstrutiva crônica; insuficiência cardíaca; doenças do colágeno; silicose; cirurgia torácica prévia; e espirometria inaceitável ou não realizada. Os campos pulmonares foram divididos em seis zonas e os radiogramas classificados em: grau I, com mínimo envolvimento em somente uma zona sem cavitação; grau II, com envolvimento de duas ou três zonas ou uma zona com cavitação; grau III, com envolvimento grave em mais de três zonas com ou sem cavitação. RESULTADOS: Cinqüenta pacientes foram incluídos no estudo e 44 deles tiveram tuberculose pulmonar (88%). O distúrbio ventilatório combinado foi o mais prevalente, 17/50 (34%). Os distúrbios acentuados foram mais significativos no grau III (p = 0,0002). A função pulmonar normal predominou nos graus I e II (p = 0,002). CONCLUSÃO: A descoberta e o tratamento precoce dos casos de tuberculose pulmonar contribuem para a diminuição dos casos da doença e de suas seqüelas, melhorando a qualidade de vida desses pacientes. Os autores sugerem uma análise logitudinal e seqüencial (protocolo), com maior número de pacientes com seqüelas de tuberculose nos serviços de referência no Brasil.
Prevalência e fatores associados à tuberculose em pacientes soropositivos para o vírus da imunodeficiência humana em centro de referência para tratamento da síndrome da imunodeficiência adquirida na região sul do Rio Grande do Sul
Authors: Silveira Jussara Maria , Sassi Raúl Andrés Mendoza , Oliveira Netto Isabel Cristina de , Hetzel Jorge Lima
Published: August 2006

OBJETIVO: Considerando a relevância da co-infecção vírus da imunodeficiência humana/tuberculose, este estudo foi desenvolvido para determinar a prevalência e os fatores associados à tuberculose em pacientes residentes em uma zona de alta prevalência das duas infecções. MÉTODOS: Todos os pacientes atendidos no ano de 1999 no Serviço HIV/AIDS do Hospital Universitário da Universidade Federal do Rio Grande foram avaliados retrospectivamente desde o momento do diagnóstico da presença do vírus da imunodeficiência humana, em relação à ocorrência de tuberculose e sua associação com fatores sociodemográficos, comportamentais e imunológicos. RESULTADOS: A amostra incluiu 204 pacientes e a prevalência encontrada de tuberculose foi de 27%. A análise multivariada mostrou que existe uma associação significativa do desenvolvimento de tuberculose com a raça negra (razão de chance: 4,76; intervalo de confiança de 95%: 1,93 -11,72) e uma relação inversa com a contagem de linfócitos TCD4+ no momento do diagnóstico do vírus da imunodeficiência humana (razão de chance: 0,995; intervalo de confiança de 95%: 0,993-0,997). O sexo masculino (razão de chance: 2,49; intervalo de confiança de 95%: 1,15-5,39) e o uso de drogas (razão de chance: 2,1; intervalo de confiança: 95% de 1,02-4,31) podem também ser fatores de risco quando analisados separadamente. CONCLUSÃO: Os fatores responsáveis pelo desenvolvimento da tuberculose entre os pacientes soropositivos para o vírus da imunodeficiência humana incluem os aspectos imunitários e fatores socioeconômicos e demográficos. A alta taxa de tuberculose em pacientes soropositivos torna urgente implementar estratégias que combinem rápida identificação e tratamento dos casos, comunicantes e indivíduos com infecção latente.
Novas terapias ergogênicas no tratamento da doença pulmonar obstrutiva crônica
Authors: Villaça Debora Strose , Lerario Maria Cristina , Dal Corso Simone , Neder José Alberto
Published: August 2006

A doença pulmonar obstrutiva crônica é considerada, atualmente, uma doença sistêmica, cujas alterações estruturais e metabólicas podem levar à disfunção muscular esquelética. Esta afeta negativamente o desempenho muscular respiratório e periférico, a capacidade funcional, a qualidade de vida relacionada à saúde e mesmo a sobrevida. A indicação de suplementação de substâncias ergogênicas para pacientes com doença pulmonar obstrutiva crônica baseia-se no fato de que estas drogas podem evitar, ou minimizar, o catabolismo e/ou estimular a síntese protéica, diminuindo a depleção de massa muscular e aumentando a capacidade de exercício. A presente revisão sumariza o conhecimento disponível acerca da utilização de esteróides anabolizantes, creatina, L-carnitina, aminoácidos de cadeia ramificada e hormônio de crescimento em pacientes com doença pulmonar obstrutiva crônica. A vantagem do uso dessas substâncias ergogênicas parece residir no aumento da massa magra e/ou na indução de modificações bioenergéticas. Nesse contexto, a maior experiência acumulada é com os esteróides anabolizantes. Entretanto, os benefícios clínicos em relação à melhora da capacidade de exercício e força muscular, bem como os efeitos na morbimortalidade, não foram, até a presente data, consistentemente demonstrados. A suplementação ergogênica pode vir a se constituir numa ferramenta adjuvante para o tratamento de pacientes com doença pulmonar obstrutiva crônica avançada, especialmente naqueles com depleção muscular e/ou fraqueza periférica.
Morphometric study of the postnatal growth of the parotid gland of the mouse
Authors: Ribeiro Tiago Turri de Castro , Sottovia André Dotto , Cestari Tania Mary , Taga Rumio
Published: August 2006

The growth of the mouse parotid glands during 7 and 35 days of postnatal life was studied by morphometric methods. The mass of the gland, the volume of each morphological compartment, and the cell number in each compartment were evaluated. The data obtained for each evaluated dimension were adjusted by an exponential equation, of the type Y = a.e k.x, thus permitting the calculation of their mean duplication time (T D), i.e., an estimation of their growth rate. Analysis of the results showed a marked 1,424% increase in the gland mass during the whole studied period, with T D = 7.10 days. This growth occurred by increases in absolute volume of acini, intercalated ducts, striated ducts, excretory ducts and stroma, with percentual increases of 3,048%, 417%, 2,662%, 2,594% and 367%, respectively, and T Ds of 5.62, 11.71, 5.55, 5.47 and 14.45 days, respectively. Analysis of the cell number growth in each compartment showed increases of 1,904%, 285%, 1,228%, 1,090% and 286%, respectively, and T Ds of 6.62, 20.40, 7.19, 7.26 and 14.51 days, respectively. Based on the present results, we concluded that the growth of the mouse parotid glands from day 7 to day 35 of age occurred by intense cell accumulation, mainly in the acini, striated ducts and excretory ducts, with a growth rate sensibly higher than that of the intercalated ducts and stroma.
The influence of the surgical operating microscope in locating the mesiolingual canal orifice: a laboratory analysis
Authors: Coutinho Filho Tauby , Cerda Renata Sá La , Gurgel Filho Eduardo Diogo , Deus Gustavo André de , Magalhães Karen Machado
Published: August 2006

The aim of this study was to evaluate the influence of using the surgical operating microscope (SOM) for detection of the mesiolingual (ML) canal orifice in extracted first maxillary permanent molars. One hundred and eight human first maxillary permanent molars were randomly selected and mounted onto a dental chair mannequin. Conventional access cavity was prepared and an attempt was made to locate the mesiolingual canal orifice using only a sharp explorer, a mirror and a #10 K-file. A mesiolingual canal orifice was either located or not located. If not located, the teeth were then evaluated by using a surgical operating microscope (SOM). The mesiobuccal roots of all teeth where the ML canal orifice had not been located were sectioned in an axial plane and the sections were explored with an adjunctive use of the SOM at a 25 X magnification. ML canal orifices were detected in 58 teeth using only a sharp explorer, a mirror and #10 K-file. In the remaining 50 teeth, 37 ML canal orifices were located by using the SOM and 3 ML canal orifices were located after root sectioning. In 10 teeth, the ML canal orifices were not found. The results of this study showed a high incidence of a ML canal in the mesiobuccal roots of the first maxillary molars (90.7%) and demonstrated that the adjunctive use of the SOM increased the ability of the dental clinician to locate the ML canal orifice.
Enhancement of muscle glucose uptake by the vasopeptidase inhibitor, omapatrilat, is independent of insulin signaling and the AMP kinase pathway
Authors: Wong Victor , Szeto Linda , Uffelman Kristine , Fantus I George , Lewis Gary F
Published: August 2006

Omapatrilat (OMA), a vasopeptidase inhibitor (VPI), presently being tested in clinical trials for its antihypertensive properties, inhibits both angiotensin-converting enzyme and neutral endopeptidase, and raises tissue bradykinin levels. Recent studies from our laboratory and those of others have demonstrated that VPIs enhance muscle glucose uptake in animal models, and this effect is mediated by the bradykinin–nitric oxide pathway. The mechanism of the effect of OMA on muscle glucose uptake, however, is presently unknown. To investigate the effect of OMA on insulin signaling, soleus muscle was isolated 2 or 5 min after an i.v. bolus of insulin or saline from male Zucker fatty rats (8–10 weeks of age), following a 5-day treatment period of oral OMA (15 mg/kg per day) or drug vehicle (placebo). OMA resulted in significantly lower systolic blood pressure compared with the placebo-treated group (84.4± 7.52 mmHg in OMA vs 112±2.18 mmHg in controls, P<0.01). Immunoprecipitation and Western blot analysis of insulin receptor substrate 1 (IRS-1) revealed no changes in protein mass with OMA treatment. OMA did not enhance basal or insulin-stimulated IRS-1 tyrosine phosphorylation or its subsequent association with the p85 regulatory subunit of phosphatidylinositol 3-kinase. Under basal and insulin-stimulated conditions, OMA treatment did not alter the protein mass or the phosphorylation of Akt/protein kinase B, p42/44 extracellular signal-regulated kinase or adenosine monophosphate-activated protein kinase, or GLUT4 protein expression. We conclude that the ability of OMA to enhance whole body and specifically muscle glucose uptake in Zucker fatty rats is not mediated by enhancing insulin or AMPK signaling. Future studies should examine whether hemodynamic effects of the drug, independent of insulin signaling, enhance glucose uptake in insulin-resistant skeletal muscle.
Sexual dimorphism in insulin sensitivity and susceptibility to develop diabetes in rats
Authors: Vital Paz , Larrieta Elena , Hiriart Marcia
Published: August 2006

The goal of this study was to evaluate gender-related differences of some metabolic determinants of insulin sensitivity and of susceptibility to the effects of diabetes. Changes in body weight, blood glucose, and serum insulin concentrations were compared between female and male Wistar rats in prepubertal, pubertal, and adult stages of life. A diabetic model was induced by streptozotocin (STZ) under nicotinamide protection in both sexes and metabolic patterns were evaluated during the next 4 weeks. Finally, the pancreases were processed for morphometric analysis. In the three age groups, at similar blood glucose levels, higher fasting serum insulin levels were found in female as compared with age matched male rats. After STZ treatment, female rats show lower insulin and higher glucose levels, and a worse survival rate as compared with male rats. The more severe disease phenotype observed in female animals is associated with a more dramatic perturbation of pancreatic islet morphology. Significant differences exist in insulin sensitivity between sexes, females being less sensitive to insulin than males at all age groups and more susceptible to the rapid development of a more severe form of diabetes than males.
Estrogen-triggered delays in mammary gland gene expression during the estrous cycle: evidence for a novel timing system
Authors: Silberstein Gary B , Van Horn Katharine , Hrabeta-Robinson Eva , Compton Jennifer
Published: August 2006

During the estrous cycle and beginning in estrus, the mammary gland undergoes pregnancy-like development that depends on transcriptional regulation by the estrogen and progesterone receptors (ER, PR) and Pax-2 as well as the action of the growth factors Wnt-4 and RANKL. In this report, we first describe the decay and delayed expression of ERα, PR, and Pax-2 proteins as well as depression of Wnt-4 and RANKL mRNA coincident with the strong estrogen surge in proestrus. In time-course studies using ovari-ectomized mice, a single estrogen injection replicated these delays and caused an 18 h delay in Wnt-4 expression. Molecular time-delay systems are at the core of cellular cycles, most notably the circadian clock, and depend on proteasome degradation of transcriptional regulators that exhibit dedicated timing functions. The cytoplasmic dynamics of these regulators govern delay duration through negative transcription/translation feedback loops. A proteasome inhibitor, PS-341, blocked estrogen-stimulated ERα, PR, and Pax-2 decay and proteasome chymotryptic activity, assayed using a fluorogenic substrate, was elevated in proestrus correlating with the depletion of the transcription factors. The 18-h delay in Wnt-4 induction corresponded to the turnover time of Pax-2 protein in the cytoplasm and was eliminated in Pax-2 knockout mammary tissue, demonstrating that Pax-2 has a unique timing function. The patterns of estrogen-triggered ERα, PR, and Pax-2 turnover were consistent with a negative transcriptional feedback. Retarding the expression of ERα, PR, and Pax-2 may optimize preparations for pregnancy by coordinating expression of critical receptors and transcription factors with rising estrogen and progesterone levels in estrus. The estrogen surge in proestrus has no defined mammotropic function. This study provides the first evidence that it is a synchronizing signal triggering proteasome-dependent turnover of mammary gland ERα, PR, and Pax-2. We hypothesize that the delays reflect a previously unrecognized timing system, which is present in all ovarian target tissues.
Peripheral administration of the N-terminal pro-opiomelanocortin fragment 1–28 to Pomc−/− mice reduces food intake and weight but does not affect adrenal growth or corticosterone production
Authors: Coll Anthony P , Fassnacht Martin , Klammer Steffen , Hahner Stephanie , Schulte Dominik M , Piper Sarah , Tung Y C Loraine , Challis Benjamin G , Weinstein Yacob , Allolio Bruno , O’Rahilly Stephen , Beuschlein Felix
Published: August 2006

Pro-opiomelanocortin (POMC) is a polypeptide precursor that undergoes extensive processing to yield a range of peptides with biologically diverse functions. POMC-derived ACTH is vital for normal adrenal function and the melanocortin α-MSH plays a key role in appetite control and energy homeostasis. However, the roles of peptide fragments derived from the highly conserved N-terminal region of POMC are less well characterized. We have used mice with a null mutation in the Pomc gene (Pomc−/−) to determine the in vivo effects of synthetic N-terminal 1–28 POMC, which has been shown previously to possess adrenal mitogenic activity. 1–28 POMC (20 μg) given s.c. for 10 days had no effect on the adrenal cortex of Pomc−/− mice, with resultant cortical morphology and plasma corticosterone levels being indistinguishable from sham treatment. Concurrent administration of 1–28 POMC and 1–24 ACTH (30 μg/day) resulted in changes identical to 1–24 ACTH treatment alone, which consisted of upregulation of steroidogenic enzymes, elevation of corticosterone levels, hypertrophy of the zona fasciculate, and regression of the X-zone. However, treatment of corticosterone-depleted Pomc−/− mice with 1–28 POMC reduced cumulative food intake and total body weight. These anorexigenic effects were ameliorated when the peptide was administered to Pomc−/− mice with circulating corticosterone restored either to a low physiological level by corticosterone-supplemented drinking water (CORT) or to a supraphysiological level by concurrent 1–24 ACTH administration. Further, i.c.v. administration of 1–28 POMC to CORT-treated Pomc−/− mice had no effect on food intake or body weight. In wild-type mice, the effects of 1–28 POMC upon food intake and body weight were identical to sham treatment, but 1–28 POMC was able to ameliorate the hyperphagia induced by concurrent 1–24 ACTH treatment. In a mouse model which lacks all endogenous POMC peptides, s.c. treatment with synthetic 1–28 POMC alone can reduce food intake and body weight, but has no impact upon adrenal growth or steroidogenesis.
The melanocortin circuit in obese and lean strains of chicks
Authors: Hen Gideon , Yosefi Sara , Simchaev Victoria , Shinder Dmitry , Hruby Victor J , Friedman-Einat Miriam
Published: August 2006

Agonists of membranal melanocortin 3 and 4 receptors (MC3/4Rs) are known to take part in the complex control mechanism of energy balance. In this study, we compared the physiological response to an exogenous MC3/4R agonist and the hypothalamic expression of proopic melanocortin (POMC) gene, encoding few MC3/4R ligands, between broiler and layer chicken strains. These strains, representing the two most prominent commercial strains of chickens grown for meat (broilers) and egg production (layers), differ in their food intake, fat accumulation, and reproductive performance and, therefore, form a good model of obese and lean phenotypes, respectively. A single i.v. injection of the synthetic peptide melanotan-II (MT-II; 1 mg/kg body weight) into the wing vein of feed-restricted birds led to attenuation of food intake upon exposure to feeding ad libitum in both broiler and layer chickens. A study of the POMC mRNA encoding the two prominent natural MC3/4R agonists, α-MSH and ACTH, also revealed a general similarity between the strains. Under feeding conditions ad libitum, POMC mRNA levels were highly similar in chicks of both strains and this level was significantly reduced upon feed restriction. However, POMC mRNA down-regulation upon feed restriction was more pronounced in layers than in broilers. These results suggest: (i) a role for MC3/4R agonists in the control of appetite; (ii) that the physiological differences between broilers and layers are not related to unresponsiveness of broiler chickens to the satiety signal of MC3/4R ligands. Therefore, these findings suggest that artificial activation of this circuit in broiler chicks could help to accommodate with their agricultural shortcomings of overeating, fattening, and impaired reproduction.
Effect of age on progesterone receptor expression, and osteoprogenitor proliferation and differentiation in female rat vertebral cell populations
Authors: Pei Weidong , Bellows Carlton G , Jia Yongheng , Heersche Johan N M
Published: August 2006

In the present investigation, we evaluated whether the capacity for proliferation and differentiation of progesterone (Prog)-dependent osteoprogenitors in the female rat skeleton is related to the level of Prog receptors (PRs) and/or the level of circulating estrogen. We confirmed that in rats, estrogen levels at 18 months of age are higher than those at 3 months, and higher again in rats of 22.5, 25.5, and 26 months of age. Prog levels in rats of ages between 18 and 25.5 months were lower than those at 26 and 3 months of age. PR-A levels were tenfold higher than those of PR-B in cell populations where PR-B was detectable; PR-B receptors were not detectable in all cell populations. In populations derived from 22.5 to 26 months old rats, the basal levels of PR-A were higher than those derived from 3 and 18 months old rats by five- and twofold respectively. Prog treatment enhanced PR-A expression in animals of all ages. Estrogen enhanced the effect of Prog on PR-A expression in cell populations from the 3 and 18 months old rats, but had no effect on PR-A expression in cell populations from 22.5, 25.5, and 26 months old rats. This might be related to the high basal expression of PR in 22.5–26 months old rats (the ‘persistent estrous’ phase). Our results also confirm our previous observation that in rats, the number of Prog- and dexamethasone (Dex)- dependent osteoprogenitors, and the effect of estrogen on the response to Prog do not decrease with age. In conclusion, we have shown that the basal level of PR-A was increased in old rats, and that this correlated with increased serum estrogen levels, but not with the number of detectable Prog-dependent osteoprogenitors. We also found that Prog upregulates the expression of its own receptors and that estrogen enhances this in young rats but not in rats over 22.5 months of age, in which estrogen levels are elevated.
G protein-coupled receptor kinase 2 and β-arrestins are recruited to FSH receptor in stimulated rat primary Sertoli cells
Authors: Marion Sébastien , Kara Elodie , Crepieux Pascale , Piketty Vincent , Martinat Nadine , Guillou Florian , Reiter Eric
Published: August 2006

FSH-receptor (FSH-R) signaling is regulated by agonist-induced desensitization and internalization. It has been shown, in a variety of overexpression systems, that G protein-coupled receptor kinases (GRKs) phosphorylate the activated FSH-R, promote β-arrestin recruitment and ultimately lead to internalization. The accuracy of this mechanism has not yet been demonstrated in cells expressing these different molecules at physiological levels. Using sucrose gradient fractionation, we show that FSH induces the recruitment of the endogenous GRK 2 and β-arrestin 1/2 from the cytoplasm to the plasma membrane of rat primary Sertoli cells. As assessed by ligand binding, the FSH-R was found expressed in the fractions where GRK 2 and β-arrestins were recruited upon FSH treatment. In addition, the endogenous β-arrestin 1 was found dephosphorylated in an agonist-dependent manner. Finally, a significant FSH-binding activity was co-immunoprecipitated with the endogenous β-arrestins from agonist-stimulated but not from untreated Sertoli cell extracts. This FSH-R interaction with β-arrestins was sustained for up to 30 min. In conclusion, our data strongly suggest that the GRK/β-arrestin machinery plays a physiologically relevant role in the regulation of the FSH signaling.
A Comparative Study of Hispanic‐American and Anglo‐American Cultural Values and Job Choice Preferences
Authors: Stone Dianna L. , Johnson Richard D. , Stone‐Romero Eugene F. , Hartman Mark
Published: August 2006

Using data from 184 employed Hispanic‐American and Anglo‐American participants in the United States, the present study examined the relations between four cultural values (i.e., collectivism, power distance, familism, present time orientation) and job choice preferences. Results revealed that (1) collectivism was positively related to the importance of coworkers and working in a diverse organization, (2) familism was related to preferences for jobs with personal time off, and (3) power distance was related to the importance of organizational reputation and promotion opportunities. In addition, the findings revealed that, relative to Anglo‐Americans, Hispanic Americans felt that organizational reputation, flexible work hours, bonuses, and diversity were more important job choice factors. Implications are offered for conducting future research on job choice and developing recruitment practices in multicultural organizations in the United States.
A Field Study of Workplace Organization on Company Performance
Authors: Ortega Raquel , Galve Carmen
Published: August 2006

Using longitudinal data over a 132‐month period collected from 500 employees of the Spanish subsidiary of the German BSHG Corporation, this paper builds upon the growing research on high‐performance work systems (HPWS) to provide a model to predict outcomes of work teams on manufacturing performance. We suggest that this issue is not exclusively dependent on having an HPWS environment. We suggest other contingent factors, such as technology and work organization, history, culture and values; and, at the same time, it is necessary to consider aspects related to attitudinal and behavioral performance.
Optimal design of batch‐storage network with uncertainty and waste treatments
Authors: Yi Gyeongbeom , Reklaitis Gintaras V.
Published: August 2006

The aim of this study was to find an analytic solution to the problem of determining the optimal capacity of a batch‐storage network to meet the demand for finished products in a system undergoing random failures of operating time and/or batch material. The superstructure of the plant considered here consists of a network of serially and/or parallel interlinked batch processes and storage units. The production processes transform a set of feedstock materials into another set of products with constant conversion factors. The final product demand flow is susceptible not only to short‐term random variations in the cycle time and batch size but also to long‐term variations in the average trend. Some of the production processes have random variations in product quantity. The spoiled materials are treated through regeneration or waste disposal processes. All other processes have random variations only in the cycle time. The objective function of the optimization is minimizing the total cost, which is composed of setup and inventory holding costs as well as the capital costs of constructing processes and storage units. A novel production and inventory analysis, the PSW (periodic square wave) model, provides a judicious graphical method to find the upper and lower bounds of random flows. The advantage of this model is that it provides a set of simple analytic solutions while also maintaining a realistic description of the random material flows between processes and storage units; as a consequence of these analytic solutions, the computation burden is substantially reduced. The proposed method has the potential to rapidly provide very useful data on which to base investment decisions during the early plant design stage. It should be of particular use when these decisions must be made in a highly uncertain business environment. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Vergleichende Untersuchungen von Standard‐Klimadatensätzen (Testreferenzjahren) mit gemessenen Langzeit‐Klimadatensätzen für den Standort Kassel
Authors: Hauser Gerd , Kempkes Christoph , Schlitzberger Stephan
Published: August 2006

Für einen innerstädtischen Standort in Kassel werden repräsentative TRY‐Datensätze mit einem meßtechnisch gewonnenen Langzeit‐Klimadatensatz insbesondere in Hinblick auf die Verwendung bei der thermischen Gebäudesimulation verglichen. Grundlage dieser Untersuchungen stellen Klimamessungen der Wetterstation des Fachgebiets Bauphysik an der Universität Kassel von 1994 bis 2003 dar. Sowohl die Auswertung der Temperaturmittelwerte als auch die der Übertemperaturgradstunden legen dar, daß das Testreferenzjahr im Sommer deutlich tiefere Außentemperaturen als der 10‐Jahres‐Durchschnitt der Messungen beinhaltet. Nicht nur das TRY‐Normaljahr, sondern auch der Datensatz des DWD für einen extrem warmen Sommer erweist sich dabei als nicht repräsentativ. Im Winterfall gibt das Normaljahr die mittleren, gemessenen Verhältnisse recht gut wieder. Die TRY‐Außentemperatur für den “kalten Winter” liegt im Januar und Februar jedoch deutlich unter den Werten der kältesten Meßperioden. Der Vergleich von Simulationsergebnissen mit den verschiedenen Klimadatensätzen zeigt, daß die Abweichungen in den Klimadatensätzen auch zu deutlichen Unterschieden in den rechnerisch ermittelten Temperaturverhältnissen im Sommer und im Heizwärmebedarf führt. Die Dekade von 1990 bis 2003 ist bekanntermaßen eine der wärmsten Dekaden seit Beginn der Wetteraufzeichnungen. Ob die dargestellten Abweichungen hierauf oder eher auf die stark unterschiedliche Topographie des Referenzstandortes gegenüber der Meßstation zurückzuführen ist, kann anhand der Untersuchung nicht geklärt werden, vermutlich liegt eine Überlagerung beider Einflüsse vor. Die Untersuchung zeigt aber quantitativ auf, welche Fehlerbandbreite sich bei der Verwendung von Referenzklimadaten ergeben kann.
Optically active trans‐2‐aminocyclopentanols: Chemoenzymatic preparation and application as chiral ligands
Authors: González‐Sabín Javier , Gotor Vicente , Rebolledo Francisca
Published: August 2006

Optically active trans‐2‐(N,N‐dialkylamino)cyclopentanols and their acetates derivatives were obtained with very good chemical yields and enantiomeric excesses (95–≥99%), through a chemoenzymatic methodology based on the lipase‐catalyzed acylation of the hydroxyl group. The utility of these compounds was shown by the preparation of the cyclopentylic analog of vesamicol and by their use as ligands in the enantioselective addition of diethylzinc to benzaldehyde.
Kinetics of biodegradation of p‐xylene and naphthalene and oxygen transfer in a novel airlift immobilized bioreactor
Authors: Jajuee Babak , Margaritis Argyrios , Karamanev Dimitre , Bergougnou Maurice A.
Published: August 2006

The scope of this study included the biodegradation performance and the rate of oxygen transfer in a pilot‐scale immobilized soil bioreactor system (ISBR) of 10‐L working volume. The ISBR was inoculated with an acclimatized population of contaminant degrading microorganisms. Immobilization of microorganisms on a non‐woven polyester textile developed the active biofilm, thereby obtaining biodegradation rates of 81 mg/L · h and 40 mg/L · h for p‐xylene and naphthalene, respectively. Monod kinetic model was found to be suitable to correlate the experimental data obtained during the course of batch and continuous operations. Oxygen uptake and transfer rates were determined during the batch biodegradation process. The dynamic gassing‐out method was used to determine the oxygen uptake rate (OUR) and volumetric oxygen mass transfer, KL a. The maximum volumetric OUR of 255 mg O2/L · h occurred approximately at 720–722 h after inoculation, when the dry weight of biomass concentration was 0.67 g/L. Biotechnol. Bioeng. 2007;96: 232–243. © 2006 Wiley Periodicals, Inc.