Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 66
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Mol Ecol ; 26(20): 5484-5499, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28833842

RESUMO

Range and niche expansion are commonly associated with transitions to asexuality, polyploidy and hybridity (allopolyploidy) in plants. The ability of asexual polyploids to colonize novel habitats may be due to widespread generalist clones, multiple ecologically specialized clones, or may be a neutral by-product of multiple, independent origins of asexual polyploids throughout the range. We have quantified niche size and divergence for hawthorns of the Pacific Northwest using data from herbarium vouchers with known cytotypes. We find that all polyploid niches diverge from that of the diploid range, and allopolyploids have the broadest niches. Allotetraploids have the largest niche and the widest geographic distribution. We then assessed the genetic mechanism of range expansion by surveying the ecological and geographic distribution of genotypes within each cytotype from sites in which fine-scale habitat assessments were completed. We find no isolation by either geographic or ecological distance in allopolyploids, suggesting high dispersal and colonization ability. In contrast, autotriploids and diploids show patterns of isolation by geographic distance. We also compared the geographic and ecological distributions of clonal genotypes with those of randomly drawn sites of the most widespread cytotype. We found that most clones are geographically widespread and occur in a variety of habitats. We interpret these findings to suggest that patterns of range and niche expansion in Pacific Northwest Hawthorns may stem from these widespread, ecologically generalist clones of hybrid origin.


Assuntos
Crataegus/genética , Ecossistema , Genética Populacional , Poliploidia , Crataegus/fisiologia , DNA de Plantas/genética , Diploide , Variação Genética , Genótipo , Geografia , Repetições de Microssatélites , Noroeste dos Estados Unidos , Dispersão Vegetal , Reprodução Assexuada
2.
Ann Bot ; 114(2): 253-69, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24984714

RESUMO

BACKGROUND AND AIMS: The taxonomic complexity of Crataegus (hawthorn; Rosaceae, Maleae), especially in North America, has been attributed by some to hybridization in combination with gametophytic apomixis and polyploidization, whereas others have considered the roles of hybridization and apomixis to be minimal. Study of the chemical composition and therapeutic value of hawthorn extracts requires reproducible differentiation of entities that may be difficult to distinguish by morphology alone. This study sought to address this by using the nuclear ribosomal spacer region ITS2 as a supplementary DNA barcode; however, a lack of success prompted an investigation to discover why this locus gave unsatisfactory results. METHODS: ITS2 was extensively cloned so as to document inter- and intraindividual variation in this locus, using hawthorns of western North America where the genus Crataegus is represented by only two widely divergent groups, the red-fruited section Coccineae and the black-fruited section Douglasia. Additional sequence data from selected loci on the plastid genome were obtained to enhance further the interpretation of the ITS2 results. KEY RESULTS: In the ITS2 gene tree, ribotypes from western North American hawthorns are found in two clades. Ribotypes from diploid members of section Douglasia occur in one clade (with representatives of the east-Asian section Sanguineae). The other clade comprises those from diploid and polyploid members of section Coccineae. Both clades contribute ribotypes to polyploid Douglasia. Data from four plastid-derived intergenic spacers demonstrate the maternal parentage of these allopolyploids. CONCLUSIONS: Repeated hybridization between species of section Douglasia and western North American members of section Coccineae involving the fertilization of unreduced female gametes explains the observed distribution of ribotypes and accounts for the phenetic intermediacy of many members of section Douglasia.


Assuntos
Evolução Biológica , Núcleo Celular/genética , Crataegus/genética , DNA Espaçador Ribossômico/genética , Frutas/genética , Plastídeos/genética , Sequência de Bases , Variação Genética , Hibridização Genética , Modelos Biológicos , América do Norte , Conformação de Ácido Nucleico , Filogenia , Poliploidia , Especificidade da Espécie
3.
Br J Cancer ; 107(2): 388-99, 2012 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-22644296

RESUMO

BACKGROUND: Previously, using gene-knockdown techniques together with genome expression array analysis, we showed the gene protein Kinase C (PKC)-zeta (PRKCZ) to mediate the malignant phenotype of human prostate cancer. However, according to NCBI, the gene has undergone several major iterations. Therefore, to understand the relationship between its structure and biological activities, we have analysed its expressed sequence in prostate cancer cell lines and tissues. METHODS: Transcriptome-walking and targeted PCR were used to sequence the mRNA transcribed from PRKCZ. Hydropathy analysis was employed to analyse the hypothetical protein sequence subsequently translated and to identify an appropriate epitope to generate a specific monoclonal antibody. RESULTS: A novel sequence was identified within the 3'-terminal domain of human PRKCZ that, in prostate cancer cell lines and tissues, is expressed during transcription and thereafter translated into protein (designated PKC-ζ(-PrC)) independent of conventional PKC-ζ(-a). The monoclonal antibody detected expression of this 96 kD protein only within malignant prostatic epithelium. INTERPRETATION: Transcription and translation of this gene sequence, including previous intronic sequences, generates a novel specific biomarker of human prostate cancer. The presence of catalytic domains characteristic of classic PKC-ß and atypical PKC-ι within PKC-ζ(-PrC) provides a potential mechanism for this PRKCZ variant to modulate the malignant prostatic phenotype out-with normal cell-regulatory control.


Assuntos
Biomarcadores Tumorais/biossíntese , Biomarcadores Tumorais/genética , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/genética , Proteína Quinase C/biossíntese , Proteína Quinase C/genética , Sequência de Aminoácidos , Sequência de Bases , Biomarcadores Tumorais/metabolismo , Domínio Catalítico , Linhagem Celular , Linhagem Celular Tumoral , Células Epiteliais/metabolismo , Variação Genética , Humanos , Masculino , Dados de Sequência Molecular , Fenótipo , Neoplasias da Próstata/metabolismo , Proteína Quinase C/metabolismo , Splicing de RNA , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Transcrição Gênica , Transcriptoma/genética
4.
Int J Nurs Stud ; 107: 103566, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32380261

RESUMO

BACKGROUND: Sexual health is an integral part of overall health in older age. Research consistently reports that heterosexual and queer older people tend not to disclose sexual concerns and difficulties which increases the risks for sexually transmitted diseases. Older people are often absent from policies and information programmes and healthcare providers experience difficulties in initiating conversations around sexual health and history. OBJECTIVES: To identify what are the barriers that stop older people seeking sexual health advice and treatment. DESIGN AND METHOD: A scoping review methodology was employed. Published and unpublished literature was scoped through development of a research question, identification of potentially relevant studies, selection of relevant studies using an iterative team approach, charting data, collating, summarising and reporting findings, and considering the implications of study findings for further research. DATA SOURCES: Electronic databases searches were run to identify published and unpublished literature, including Medline, Embase, PsycINFO, CINAHL, ASSIA, Social Sciences, RCN and Cochrane Libraries. Additional studies were located through hand searching. RESULTS: Twelve studies from: the USA (n = 6); the UK (n = 3); Australia (n = 2); and one shared paper between New Zealand and UK met the inclusion criteria. Four barriers that stop older people seeking sexual health advice and treatment were identified, including (1) Cultural and societal views and beliefs toward sexual health; (2) Stigma, embarrassment and discrimination; (3) Lack of education and training of healthcare professionals; (4) Quality of relationship between patients and health professionals. CONCLUSION: Barriers to seeking and receiving advice and treatment for sexual health in later life clearly exist and are both related to cultural and social factors. Overall, the papers reviewed in this scoping review indicate that healthcare providers are reluctant to initiate conversations around sexual health or offer appropriate advice or clinical tests, and that older people tend to be hesitant to seek medical help. Later life age groups independently from their sexual orientation represent a hidden population and are absent from sexual health campaigns and government policies. Efforts need to be made by influential institutions and healthcare providers to recognise sexuality in older age and give older people the opportunity to open up regarding their sexual health and experiences.


Assuntos
Promoção da Saúde/métodos , Saúde Sexual/educação , Minorias Sexuais e de Gênero/psicologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Geriatria/métodos , Promoção da Saúde/estatística & dados numéricos , Humanos , Masculino , Relações Profissional-Paciente , Saúde Sexual/estatística & dados numéricos , Minorias Sexuais e de Gênero/estatística & dados numéricos
5.
Science ; 256(5065): 1817-20, 1992 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-1319610

RESUMO

Between 650 and 2000 different peptides are associated with the major histocompatibility complex class II molecule I-Ad. Sequences for nine of these were obtained by a combination of automated Edman degradation and tandem mass spectrometry. All of the peptides are derived from secretory or integral membrane proteins that are synthesized by the antigen-presenting cell itself. Peptides were 16 to 18 residues long, had ragged NH2-and COOH-termini, and contained a six-residue binding motif that was variably placed within the peptide chain. Binding data on truncated peptides suggest that the peptide binding groove on class II molecules can be open at both ends.


Assuntos
Antígenos de Histocompatibilidade Classe II/imunologia , Proteínas de Membrana/genética , Sequência de Aminoácidos , Animais , Células Apresentadoras de Antígenos/química , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Camundongos , Dados de Sequência Molecular , Homologia de Sequência do Ácido Nucleico
6.
Science ; 293(5529): 498-506, 2001 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-11463916

RESUMO

The 2,160,837-base pair genome sequence of an isolate of Streptococcus pneumoniae, a Gram-positive pathogen that causes pneumonia, bacteremia, meningitis, and otitis media, contains 2236 predicted coding regions; of these, 1440 (64%) were assigned a biological role. Approximately 5% of the genome is composed of insertion sequences that may contribute to genome rearrangements through uptake of foreign DNA. Extracellular enzyme systems for the metabolism of polysaccharides and hexosamines provide a substantial source of carbon and nitrogen for S. pneumoniae and also damage host tissues and facilitate colonization. A motif identified within the signal peptide of proteins is potentially involved in targeting these proteins to the cell surface of low-guanine/cytosine (GC) Gram-positive species. Several surface-exposed proteins that may serve as potential vaccine candidates were identified. Comparative genome hybridization with DNA arrays revealed strain differences in S. pneumoniae that could contribute to differences in virulence and antigenicity.


Assuntos
Genoma Bacteriano , Análise de Sequência de DNA , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/patogenicidade , Antígenos de Bactérias , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Vacinas Bacterianas , Composição de Bases , Metabolismo dos Carboidratos , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Cromossomos Bacterianos/genética , Biologia Computacional , Elementos de DNA Transponíveis , DNA Bacteriano/química , DNA Bacteriano/genética , Duplicação Gênica , Genes Bacterianos , Hexosaminas/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Recombinação Genética , Sequências Repetitivas de Ácido Nucleico , Especificidade da Espécie , Streptococcus pneumoniae/imunologia , Streptococcus pneumoniae/metabolismo , Virulência , Óperon de RNAr
7.
J Plant Res ; 122(3): 253-68, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19184674

RESUMO

The taxonomic integrity of Vaccinium section Bracteata sensu Sleumer was assessed using a variety of numerical measures on a data matrix created from 46 OTUs scored for 65 descriptors. These analyses supported a much restricted ambit for section Bracteata and the concomitant resurrection of section Nesococcus and section Euepigynium, a more cosmopolitan interpretation for section Eococcus and section Pyxothamnus as well as a new taxon, Vaccinium section Baccula-nigra Kloet, sect. nov. to accommodate V. fragile Franch. and its conspecifics. A key to all the sections as well as a brief description for each section is also provided.


Assuntos
Ecossistema , Geografia , Metamorfose Biológica , Vaccinium/classificação , Análise por Conglomerados , Flores/fisiologia , Frutas/fisiologia , Análise de Componente Principal
8.
Nucleic Acids Res ; 29(1): 123-5, 2001 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-11125067

RESUMO

One challenge presented by large-scale genome sequencing efforts is effective display of uniform information to the scientific community. The Comprehensive Microbial Resource (CMR) contains robust annotation of all complete microbial genomes and allows for a wide variety of data retrievals. The bacterial information has been placed on the Web at http://www.tigr.org/CMR for retrieval using standard web browsing technology. Retrievals can be based on protein properties such as molecular weight or hydrophobicity, GC-content, functional role assignments and taxonomy. The CMR also has special web-based tools to allow data mining using pre-run homology searches, whole genome dot-plots, batch downloading and traversal across genomes using a variety of datatypes.


Assuntos
Bactérias/genética , Bases de Dados Factuais , Genes Bacterianos/genética , Genoma Bacteriano , Serviços de Informação , Internet
9.
Trends Pharmacol Sci ; 20(8): 324-9, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10431211

RESUMO

Neuropathic pain arising from direct trauma to, or compression injury of, peripheral nerves is a common clinical problem. It is characterized by the development of abnormal pain states (spontaneous pain, hyperalgesia, allodynia), which can persist long after the initial injury has resolved. The underlying mechanisms are poorly understood and, as a consequence, treatment is often unsatisfactory. Some of the main contributing factors are thought to be the morphological and phenotypic changes that occur centrally, including alterations in the expression of neurotransmitters and their associated receptors, both in the dorsal root ganglia and in the spinal dorsal horn. This article focuses on the functional role of the two structurally related peptides VIP and PACAP within the spinal cord, and their possible contribution to the altered transmission of sensory information in neuropathic conditions.


Assuntos
Neuropeptídeos/fisiologia , Dor/fisiopatologia , Traumatismos dos Nervos Periféricos , Sistemas do Segundo Mensageiro/fisiologia , Medula Espinal/química , Peptídeo Intestinal Vasoativo/fisiologia , Animais , Gânglios Espinais/química , Dor/etiologia , Nervos Periféricos/patologia , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Ratos , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Receptores do Hormônio Hipofisário/fisiologia , Receptores de Peptídeo Intestinal Vasoativo/fisiologia , Receptores Tipo II de Peptídeo Intestinal Vasoativo , Receptores Tipo I de Polipeptídeo Intestinal Vasoativo , Sistemas do Segundo Mensageiro/efeitos dos fármacos
10.
J Psychiatr Ment Health Nurs ; 22(6): 413-22, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26122924

RESUMO

ACCESSIBLE SUMMARY: Little is known about how the prison environment may impact upon the mental health of adult prisoners. This paper highlights that prisoners perceive that the prison environment has a negative influence upon their mental health. However, a small number regarded prison as a place of respite, which afforded structure and an opportunity to access health services. There is a need for more research in this area specifically relating to the impact the prison climate may have upon those from black and minority ethic groups. Nurses must recognize the aspects of the prison environment that may impact upon the mental health of prisoners and demonstrate innovation and imagination in their application of interventions. ABSTRACT: Little is known regarding how the prison environment may affect the mental health of adult prisoners. Consequently, there is a need to investigate how this setting may exacerbate mental distress among this community. This literature review explores how the prison climate influences the mental health of adult prisoners. A thematic synthesis approach was used to elicit data relating to the aspects of the prison climate, which influence the mental health of prisoners. Four primary themes emerged from the synthesis: social, emotional, organizational and physical aspects. Prisoners perceive the prison climate to have a negative influence upon their mental health. However, perceived positively, prison was regarded as a place of respite, which afforded structure and an opportunity to access health services. There is limited research available specifically exploring the potential impact of the prison climate upon those from black and ethnic minorities groups. Nurses must recognize the aspects of the prison environment that may impact upon the mental health of prisoners and demonstrate innovation and imagination in their application of interventions. Additionally nurses need to take an active role in influencing and structuring the political agenda, which governs the clinical setting.


Assuntos
Saúde Mental/normas , Prisioneiros/psicologia , Prisões/normas , Humanos
11.
Trends Biotechnol ; 16(6): 250-8, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9652136

RESUMO

Basic principles derived from biological olfaction, such as combining semiselective sensor arrays with pattern recognition, have been used to develop instrumentation capable of broad-band chemical detection and quantification. Commercially available instruments are useful in areas including quality control in the food, beverage and fragrance industries, environmental monitoring, chemical-purity and -mixture analysis, and medical diagnostics. Ongoing research is aimed at the development of more-advanced instruments that are smaller, cheaper, faster and more stable and reliable. These second-generation instruments are likely to find an increasing number of applications, including the on-line monitoring of fermentation and other bioprocesses.


Assuntos
Processamento Eletrônico de Dados , Odorantes , Reconhecimento Automatizado de Padrão , Controle de Qualidade
12.
J Comp Neurol ; 355(1): 67-80, 1995 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-7636015

RESUMO

Hypotransferrinemic (Hp) mice have a point mutation or small deletion in the transferrin (Tf) gene, resulting in defective splicing of precursor Tf mRNA. Hp animals produce < 1% of normal Tf levels and require supplemental serum or purified Tf for survival. Because of the lack of endogenous brain Tf, we examined regional and cellular distributions of iron and iron regulatory proteins (Tf and ferritin) in selected brain regions of Hp mice. The regional distribution of iron, Tf, and ferritin in Hp brain was similar to normal except for the pattern of iron staining in hippocampus. The cellular distribution of iron, ferritin, and Tf was similar between Hp and normal animals. The predominant cell type staining for Tf and iron was oligodendrocytes. Qualitative observations suggest that the number of cells staining for iron was similar between Hp and normal mice, whereas the number of Hp Tf-positive cells was reduced. Ferritin immunostaining was similar in both cases. However, ferritin-positive cells were predominantly astrocytes, an observation unique to mice among species studied previously. Western blot analysis revealed that Tf present in Hp brain was of exogenous origin (from supplemental injections). Presumably, Tf transports the iron found in Hp oligodendrocytes. These data demonstrate that, despite reduced endogenous Hp brain Tf, iron and plasma Tf migrate or are transported to the appropriate cells (oligodendrocytes), bringing into question the role of endogenous brain Tf in extracellular iron transport.


Assuntos
Encéfalo/metabolismo , Ferritinas/farmacocinética , Ferro/farmacocinética , Transferrina/farmacocinética , Animais , Encéfalo/citologia , Camundongos , Camundongos Endogâmicos , Camundongos Mutantes , Mutação Puntual , Transferrina/genética , Transferrina/metabolismo
13.
Neuropharmacology ; 34(8): 1033-41, 1995 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8532152

RESUMO

The excitatory responses of individual dorsal horn neurons to cutaneous brush, repeated application of the C-fibre-selective chemical algogen, mustard oil, or to ionophoretic (1S,3R)-ACPD [a metabotropic glutamate receptor (mGluR) agonist] were monitored by extracellular recording. We have previously shown that the responses of dorsal horn neurons to mustard oil are inhibited by several selective antagonists of mGluRs. Effects of ionophoresis of the mGluR antagonists (R,S)-CHPG and L-AP3 and a range of selective inhibitors of intracellular signalling pathways were examined on evoked responses here. The results suggest that protein kinase C, phospholipase A2 and perhaps Ca2+/calmodulin kinase II play a role in mediating the sustained elevated activity of dorsal horn neurons that is incrementally elicited by repeated application of mustard oil, but probably make little contribution to sustained brush-evoked activity. Concurrence in the sensitivity of mustard oil- and (1S,3R)-ACPD-evoked activity to (R,S)-CHPG, L-AP3 and to inhibitors of intracellular signalling pathways, suggests that mGluRs are an important origin of these intracellular signals required for sustained nociception.


Assuntos
Neurônios/fisiologia , Dor/fisiopatologia , Receptores de Glutamato Metabotrópico/fisiologia , Medula Espinal/fisiologia , Transmissão Sináptica/fisiologia , Animais , Cicloleucina/análogos & derivados , Cicloleucina/farmacologia , Espaço Extracelular/efeitos dos fármacos , Espaço Extracelular/fisiologia , Técnicas In Vitro , Iontoforese , Masculino , Mostardeira , Neurônios/efeitos dos fármacos , Dor/induzido quimicamente , Estimulação Física , Extratos Vegetais , Óleos de Plantas , Ratos , Ratos Wistar , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Medula Espinal/citologia , Medula Espinal/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos
14.
Neuropharmacology ; 38(1): 167-80, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10193908

RESUMO

Peripheral nerve damage often results in the development of chronic pain states, resistant to classical analgesics. Since vasoactive intestinal polypeptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) are up-regulated in dorsal root ganglion cells following peripheral nerve injury, we investigated the expression and influence of VPAC1, VPAC2 and PAC1 receptors in rat spinal dorsal horn following a chronic constriction injury (CCI). Electrophysiological studies revealed that selective antagonists of VPAC1, VPAC2 and PAC1 receptors inhibit mustard oil-, but not brush-induced activity of dorsal horn neurones in CCI animals, while cold-induced neuronal activity was attenuated by VPAC1 and PAC1, but not VPAC2 receptor antagonists. Ionophoresis of selective agonists for the receptor subtypes revealed that the VPAC2 receptor agonist excited twice as many cells in CCI compared to normal animals, while the number of cells excited by the VPAC1 receptor agonist decreased and responses to PACAP-38 remained unchanged. In situ hybridisation histochemistry (ISHH) confirmed an increase in the expression of VPAC2 receptor mRNA within the ipsilateral dorsal horn following neuropathy, while VPAC1 receptor mRNA was seen to decrease and that for PAC1 receptors remained unchanged. These data indicate that VIP/PACAP receptors may be important regulatory factors in neuropathic pain states.


Assuntos
Neuralgia/fisiopatologia , Doenças do Sistema Nervoso Periférico/fisiopatologia , Receptores do Hormônio Hipofisário/fisiologia , Receptores de Peptídeo Intestinal Vasoativo/fisiologia , Sensação/fisiologia , Medula Espinal/fisiopatologia , Animais , Comportamento Animal/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Histocitoquímica/métodos , Hibridização In Situ , Masculino , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Doenças do Sistema Nervoso Periférico/etiologia , Ratos , Ratos Wistar , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Receptores do Hormônio Hipofisário/agonistas , Receptores de Peptídeo Intestinal Vasoativo/agonistas , Receptores Tipo II de Peptídeo Intestinal Vasoativo , Receptores Tipo I de Polipeptídeo Intestinal Vasoativo , Medula Espinal/efeitos dos fármacos , Estresse Mecânico , Regulação para Cima
15.
Neurosci Res ; 39(4): 385-90, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11274737

RESUMO

Some opioid-resistant pain conditions can be alleviated by voltage-dependent Na(+) channel blockers such as lamotrigine. The mu-opioid-receptor agonist morphine can modulate cation entry into cells to affect overall cellular excitability, an effect which can in turn be endogenously antagonised by the neuropeptide cholecystokinin (CCK). However, lamotrigine may also modulate cellular excitability by non-specifically blocking voltage-dependent ion channels. We have looked for interactions of lamotrigine with the opioid/CCK pathway within the spinal dorsal horn, to rule out the possibility that lamotrigine may attenuate nociceptive responses via actions on this pathway. Both lamotrigine and the mu-opioid agonist DAMGO inhibited mustard oil-evoked cell firing by approximately 50% compared with control levels. Co-application of CCK8S reversed DAMGO-, but not lamotrigine-induced inhibition of cell firing and this reversal was prevented with the selective CCK(B) receptor antagonist PD 135158. Although lamotrigine inhibited both brush- and cold-evoked cell firing in neuropathic animals, lamotrigine inhibition of mustard oil-evoked cell firing in the same animals was not significantly greater than that observed in controls. These results suggest that the antinociceptive properties of lamotrigine within the spinal dorsal horn are unlikely to be mediated via interactions with the opioid/CCK pathway.


Assuntos
Bloqueadores dos Canais de Cálcio/farmacologia , Vias Neurais/efeitos dos fármacos , Nociceptores/efeitos dos fármacos , Peptídeos Opioides/metabolismo , Dor/tratamento farmacológico , Células do Corno Posterior/efeitos dos fármacos , Triazinas/farmacologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Analgésicos Opioides/farmacologia , Animais , Ansiolíticos/farmacologia , Colecistocinina/metabolismo , Ala(2)-MePhe(4)-Gly(5)-Encefalina/farmacologia , Indóis/farmacologia , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Inflamação/fisiopatologia , Lamotrigina , Masculino , Meglumina/análogos & derivados , Meglumina/farmacologia , Mostardeira , Vias Neurais/citologia , Vias Neurais/metabolismo , Nociceptores/citologia , Nociceptores/metabolismo , Dor/metabolismo , Dor/fisiopatologia , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Doenças do Sistema Nervoso Periférico/metabolismo , Doenças do Sistema Nervoso Periférico/fisiopatologia , Extratos Vegetais/farmacologia , Óleos de Plantas , Células do Corno Posterior/citologia , Células do Corno Posterior/metabolismo , Ratos , Ratos Wistar , Sincalida/farmacologia
16.
Neuropeptides ; 31(2): 175-85, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9179871

RESUMO

The extracellularly recorded electrophysiological activity of single multireceptive dorsal horn neurons was markedly increased by ionophoretic administration of vasoactive intestinal polypeptide (VIP) or pituitary adenylate cyclase activating polypeptide (PACAP)-38. Some cells responded selectively to PACAP-38 (suggesting mediation by a PACAP receptor), whereas others responded to both VIP and PACAP-38 (suggesting a VIP1 and/or VIP2 receptor). Most non-nociceptive cells were unaffected by PACAP-38 and all were unaffected by VIP. The selectivity of VIP/PACAP receptor antagonists was established on cloned rat VIP1, VIP2 and PACAP receptors in vitro before their utilization to indicate the likely involvement of VIP1, and possibly PACAP receptors, in VIP- and PACAP-38-mediated responses of dorsal horn neurons. The VIP/PACAP receptor antagonists inhibited responses of multireceptive cells to sustained innocuous (brush) and noxious (mustard oil) stimuli, with a selectivity suggesting the involvement of VIP1 and PACAP receptors, although the participation by VIP2 receptors cannot be excluded. These data implicate both VIP and PACAP in regulating the basal responsiveness of multireceptive dorsal horn neurons to sensory stimuli.


Assuntos
Neurônios Aferentes/fisiologia , Neurônios/fisiologia , Neuropeptídeos/farmacologia , Neurotransmissores/farmacologia , Receptores do Hormônio Hipofisário/fisiologia , Receptores de Peptídeo Intestinal Vasoativo/fisiologia , Medula Espinal/fisiologia , Peptídeo Intestinal Vasoativo/farmacologia , Animais , Células COS , Masculino , Potenciais da Membrana/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fragmentos de Peptídeos/farmacologia , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Ratos , Ratos Wistar , Receptores de Polipeptídeo Hipofisário Ativador de Adenilato Ciclase , Receptores do Hormônio Hipofisário/efeitos dos fármacos , Receptores de Peptídeo Intestinal Vasoativo/efeitos dos fármacos , Receptores Tipo II de Peptídeo Intestinal Vasoativo , Proteínas Recombinantes/metabolismo , Medula Espinal/efeitos dos fármacos , Transfecção , Peptídeo Intestinal Vasoativo/análogos & derivados
17.
Biosens Bioelectron ; 13(6): 697-9, 1998 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-9828363

RESUMO

Optical sensor arrays containing fluorescent solvatochromatic dyes immobilized in a plurality of polymers generate information-rich responses upon exposure to organic vapors. The response profiles are used to train a variety of computational networks such that subsequent exposure of the array to the vapors enables them to be classified and/or quantified. A number of strategies can be taken to enhance sensitivity and to increase sensor diversity.


Assuntos
Técnicas Biossensoriais , Odorantes , Animais , Técnicas Biossensoriais/instrumentação , Tecnologia de Fibra Óptica , Humanos
18.
Brain Res ; 635(1-2): 169-78, 1994 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-8173952

RESUMO

This study utilizes a mutant mouse line (Hp) in which an established essential trophic factor, transferrin (Tf), is deficient due to a splicing defect in the processing of Tf precursor mRNA. As this mouse mutant is new to neurological research, the initial stage of the investigation, histological analysis of the brain and spinal cord, is reported here. Using a number of standard histological stains, such as hematoxylin and eosin, luxol fast blue/cresyl violet and silver staining, we see a decrease in the amount of white matter and neurofilament staining and altered neuronal morphology throughout the brain and spinal cord. Regions in which postnatal development is significant such as the hippocampus and cerebellum are particularly affected in this mutant. The cells of the dentate gyrus and Ammon's horn of the hippocampus are smaller, more densely packed and the normal orderly appearance of the CA3 and CA4 regions of Ammon's horn is disrupted. The cerebellum has a decrease in white matter and the molecular, Purkinje cell and granule cell layers all show decreased silver staining for neurofilament and appear less ordered than normal. The results demonstrate that neurohistological alterations exist in the adult hypotransferrinemic mice despite systemic replacement of transferrin. Furthermore, these data suggest certain brain regions are particularly sensitive to disruption in iron delivery. The results of this initial study indicate the Hp animal may be an interesting model for investigating specific aspects of neural development and has considerable potential for examining the importance of iron regulation in the brain.


Assuntos
Encéfalo/patologia , Transferrina/deficiência , Animais , Encéfalo/metabolismo , Cerebelo/patologia , Córtex Cerebral/patologia , Plexo Corióideo/patologia , Hipocampo/patologia , Camundongos , Camundongos Mutantes Neurológicos , Fenótipo , Medula Espinal/patologia
19.
Brain Res ; 801(1-2): 171-81, 1998 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-9729367

RESUMO

The hypotransferrinemic (hpx) mouse mutant produces <1% of the normal circulating level of transferrin (Tf). Heterozygote animals of this strain (hpx/+) have approximately 50% of normal plasma Tf levels. In this study we examine the cellular and regional distribution of Tf receptor (Tf-R) in the brain of wild type, hpx/+ and mutant (hpx/hpx) mice. Also, using slot-blot (immunoblot) analysis, we describe the relative amount of Tf-R in brain microvessels of hpx/+ animals compared with wild type. Tf-R was seen primarily in neurons throughout the brains of wild type, hpx/+ and hpx/hpx animals. Gray matter areas immunoreacted more robustly than white matter areas. Oligodendrocytes and third ventricle tanycytes, both of which we have previously described as iron-positive, did not immunoreact for Tf-R. Tf-R immunohistochemical reaction in wild type, hpx/+ and hpx/hpx brains appeared similar. Immunoblot analysis of isolated cortical microvessels from wild type and hpx/+ animals revealed no upregulation of Tf-R expression in hpx/+ (relative to normal) despite a 50% decrease in circulating Tf levels. These results indicate that Tf-R is primarily expressed by neurons and that half normal levels of Tf (hpx/+) or transferrin supplementation (hpx/hpx) are apparently sufficient for normal expression and distribution of Tf-R. Because of the lack of circulating Tf, but unaltered Tf-R expression, hpx mice could serve as a model for delivery of therapeutic agents via the Tf/Tf-R system.


Assuntos
Química Encefálica , Encéfalo/citologia , Receptores da Transferrina/análise , Transferrina/deficiência , Animais , Córtex Cerebral/irrigação sanguínea , Córtex Cerebral/citologia , Homozigoto , Imuno-Histoquímica , Ferro/sangue , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Mutantes , Especificidade de Órgãos , Transferrina/análise , Transferrina/genética
20.
Brain Res ; 777(1-2): 161-9, 1997 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-9449425

RESUMO

A combined study of behavioural and electrophysiological tests was carried out in order to assess the role of metabotropic glutamate receptors (mGluRs) in mediating sensory inputs to the spinal cord of the rat. In the behavioural study the responses of conscious animals, with or without carrageenan-induced inflammation, to noxious mechanical and thermal stimuli were observed both before and after the intrathecal administration of mGluR antagonists L(+)-2-amino-3-phosphonopropionic acid (L-AP3) and (S)-4-carboxy-3-hydroxyphenylglycine (CHPG). It was found that the mGluR antagonist (S)-CHPG was capable of increasing both mechanical threshold and thermal latency in both groups of animals, and L-AP3 did so in those with inflammation induced in their hindpaw. Following this study, the responses of single lamina III-V dorsal horn neurons to an innocuous A beta fibre brush stimulus and a noxious C fibre (mustard oil) stimulus were extracellularly recorded and the effect of ionophoretically applied drugs was examined. Cyclothiazide (CTZ), a selective antagonist at mGluR1, markedly reduced the activity evoked by mustard oil, but not that elicited by brushing of the receptive field. Activity induced in dorsal horn neurons by ionophoresing various mGluR subgroup agonists was examined. CTZ successfully inhibited the activity evoked by group I mGluR agonist 3,5-dihydroxyphenylglycine (DHPG). In comparison to the neurons which responded to the ionophoresis of DHPG, less were activated by the selective mGluR5 agonist trans-azetidine dicarboxylic acid (t-ADA). Together these results indicate that group I mGlu receptors, in particular mGluR1, play a crucial role in mediating nociception, particularly following a sustained noxious input.


Assuntos
Comportamento Animal/fisiologia , Nociceptores/fisiologia , Dor/fisiopatologia , Receptores de Glutamato Metabotrópico/fisiologia , Medula Espinal/fisiologia , Alanina/análogos & derivados , Alanina/farmacologia , Animais , Anti-Hipertensivos/farmacologia , Benzotiadiazinas/farmacologia , Cicloleucina/análogos & derivados , Cicloleucina/farmacologia , Eletrofisiologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Feminino , Glicina/análogos & derivados , Glicina/farmacologia , Masculino , Mostardeira , Fármacos Neuroprotetores/farmacologia , Nociceptores/efeitos dos fármacos , Fenilacetatos/farmacologia , Extratos Vegetais , Óleos de Plantas , Plantas Medicinais , Ratos , Ratos Endogâmicos , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Resorcinóis/farmacologia , Medula Espinal/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA