Complex Role (complex + role)

Distribution by Scientific Domains
Distribution within Medical Sciences


Selected Abstracts


Air pollution impedes plant-to-plant communication by volatiles

ECOLOGY LETTERS, Issue 9 2010
James D. Blande
Ecology Letters (2010) 13: 1172,1181 Abstract Volatile organic compounds (VOCs) emitted by damaged plants convey information to undamaged neighbouring plants, and previous research has shown that these signals are effective over short distances in nature. Many herbivore-induced VOCs react with ozone, which is the most important tropospheric air pollutant in rural areas. We used extrafloral nectar (EFN) secretion as a phenotypic indicator of between-plant communication in Phaseolus lunatus L. (Lima bean) and show that an ozone-rich (80 ppb) atmosphere reduces the distance over which signalling occurs. We found that ozone degrades several herbivore-induced VOCs, a likely mechanism reducing communication distances. Direct exposure to 80-ppb ozone did not affect the VOC emissions from P. lunatus. In addition, we demonstrated that high ozone concentrations, 120 and 160 ppb, induced EFN secretion in exposed plants, whereas more moderate concentrations, 80 and 100 ppb, did not. This suggests that ozone can play a complex role in the indirect defence of P. lunatus. [source]


Increased urinary excretion of nitric oxide metabolites in longitudinally monitored migraine patients

EUROPEAN JOURNAL OF NEUROLOGY, Issue 12 2006
K. Rejdak
This study evaluated a relationship between nitric oxide (NO) and migraine attacks in order to gain insight into migraine pathomechanism. The study groups consisted of 12 migraineurs and eight controls. All subjects collected morning urine samples for 40 consecutive days. Urinary NO metabolites, nitrite/nitrate (NOx) levels were measured with the vanadium-based assay, whilst creatinine (Cr) and neopterin were determined with high-performance liquid chromatography. The mean urinary NOx/Cr ratio and number of NOx peaks was significantly greater in the migraine group compared with controls (P = 0.01 and P = 0.007, respectively). In the second approach, high NOx values were re-assessed in relation to raised neopterin, a marker of systemic infection or inflammation, and were excluded. The excretion of NOx persisted being pulsatile, and migraineurs had more peaks compared with controls (P = 0.01). In seven patients, NOx peaks coincided with headache days. This was more frequent than expected by random association in four patients (Monte-Carlo simulation; odds ratios: 2.16,7.77; no overlap of 95% CI). In four patients, NOx peaks preceded or followed headache days. Although there is a difference in the pattern of urinary NOx excretion between control and migraine populations, the variable temporal association of NOx peaks and headaches suggests a complex role of NO in this condition. [source]


Plasticity of hair follicle dermal cells in wound healing and induction

EXPERIMENTAL DERMATOLOGY, Issue 2 2003
A. Gharzi
Abstract: The capacity of adult hair follicle dermal cells to participate in new follicle induction and regeneration, and to elicit responses from diverse epithelial partners, demonstrates a level of developmental promiscuity and influence far exceeding that of interfollicular fibroblasts. We have recently suggested that adult follicle dermal cells have extensive stem or progenitor cell activities, including an important role in skin dermal wound healing. Given that up to now tissue engineered skin equivalents have several deficiencies, including the absence of hair follicles, we investigated the capacity of follicle dermal cells to be incorporated into skin wounds; to form hair follicles in wound environments; and to create a hair follicle-derived skin equivalent. In our study, we implanted rat follicle dermal cells labelled with a vital dye into ear and body skin wounds. We found that they were incorporated into the new dermis in a manner similar to skin fibroblasts, but that lower follicle dermal sheath also assimilated into hair follicles. Using different combinations of follicle dermal cells and outer root sheath epithelial cells in punch biopsy wounds, we showed that new hair follicles were formed only with the inclusion of intact dermal papillae. Finally by combining follicle dermal sheath and outer root sheath cells in organotypic chambers, we created a skin equivalent with characteristic dermal and epidermal architecture and a normal basement membrane , the first skin to be produced entirely from hair follicle cells. These data support the hypothesis that follicle dermal cells may be important in wound healing and demonstrate their potential usefulness in human skin equivalents and skin substitutes. While we have made progress towards producing skin equivalents that contain follicles, we suggest that the failure of cultured dermal papilla cells to induce follicle formation in wounds illustrates the complex role the follicle dermis may play in skin. We believe that it demonstrates a genuine dichotomy of activity for follicle cells within skin. [source]


Role of the N- and C-terminal regions of the PufX protein in the structural organization of the photosynthetic core complex of Rhodobacter sphaeroides

FEBS JOURNAL, Issue 7 2002
Francesco Francia
The core complex of Rhodobacter sphaeroides is formed by the association of the light-harvesting antenna 1 (LH1) and the reaction center (RC). The PufX protein is essential for photosynthetic growth; it is located within the core in a 1 : 1 stoichiometry with the RC. PufX is required for a fast ubiquinol exchange between the QB site of the RC and the Qo site of the cytochrome bc1 complex. In vivo the LH1,PufX,RC complex is assembled in a dimeric form, where PufX is involved as a structural organizer. We have modified the PufX protein at the N and the C-terminus with progressive deletions. The nine mutants obtained have been characterized for their ability for photosynthetic growth, the insertion of PufX in the core LH1,RC complex, the stability of the dimers and the kinetics of flash-induced reduction of cytochrome b561 of the cytochrome bc1 complex. Deletion of 18 residues at the N-terminus destabilizes the dimer in vitro without preventing photosynthetic growth. The dimer (or a stable dimer) does not seem to be a necessary requisite for the photosynthetic phenotype. Partial C-terminal deletions impede the insertion of PufX, while the complete absence of the C-terminus leads to the insertion of a PufX protein composed of only its first 53 residues and does not affect the photosynthetic growth of the bacterium. Overall, the results point to a complex role of the N and C domains in the structural organization of the core complex; the N-terminus is suggested to be responsible mainly for dimerization, while the C-terminus is thought to be involved mainly in PufX assembly. [source]


The role of genome diversity and immune evasion in persistent infection with Helicobacter pylori

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2005
Cara L. Cooke
Abstract Helicobacter pylori is an important human pathogen that chronically colonizes the stomach of half the world's population. Infection typically occurs in childhood and persists for decades, if not for the lifetime of the host. How is bacterial persistence possible despite a vigorous innate and adaptive immune response? Here we describe the complex role of bacterial diversity and specific mechanisms to avoid or subvert host immunity in bacterial persistence. We suggest that H. pylori finely modulates the extent to which it interacts with the host in order to promote chronic infection, and that it uses diverse mechanisms to do so. [source]


Gain of a region on 7p22.3, containing MAD1L1, is the most frequent event in small-cell lung cancer cell lines

GENES, CHROMOSOMES AND CANCER, Issue 1 2006
Bradley P. Coe
Small-cell lung cancer (SCLC) is a highly aggressive lung neoplasm, which accounts for 20% of yearly lung cancer cases. The lack of knowledge of the progenitor cell type for SCLC precludes the definition of a normal gene expression profile and has hampered the identification of gene expression changes, while the low resolution of conventional genomic screens such as comparative genomic hybridization (CGH) and loss of heterozygosity analysis limit our ability to fine-map genetic alterations. The recent advent of whole genome tiling path array CGH enables profiling of segmental DNA copy number gains and losses at a resolution 100 times that of conventional methods. Here we report the analysis of 14 SCLC cell lines and six matched normal B-lymphocyte lines. We detected 7p22.3 copy number gain in 13 of the 14 SCLC lines and 0 of the 6 matched normal lines. In 4 of the 14 cell lines, this gain is present as a 350 kbp gene specific copy number gain centered at MAD1L1 (the human homologue of the yeast gene MAD1). Fluorescence in situ hybridization validated the array CGH finding. Intriguingly, MAD1L1 has been implicated to have tumor-suppressing functions. Our data suggest a more complex role for this gene, as MAD1L1 is the most frequent copy number gain in SCLC cell lines. © 2005 Wiley-Liss, Inc. [source]


Expanding the Andersen Model: The Role of Psychosocial Factors in Long-Term Care Use

HEALTH SERVICES RESEARCH, Issue 5 2002
Elizabeth H Bradley
Objective. To examine a prevailing conceptual model of health services use (Andersen 1995) and to suggest modifications that may enhance its explanatory power when applied to empirical studies of race/ethnicity and long-term care. Study Setting. Twelve focus groups of African-American (five groups) and white (seven groups) individuals, aged 65 and older, residing in Connecticut during 2000. Study Design. Using qualitative analysis, data were coded and analyzed in NUD-IST 4 software to facilitate the reporting of recurrent themes, supporting quotations, and links among the themes for developing the conceptual framework. Specific analysis was conducted to assess distinctions in common themes between African-American and white focus groups. Data Collection. Data were collected using a standardized discussion guide, augmented by prompts for clarification. Audio taped sessions were transcribed and independently coded by investigators and crosschecked to enhance coding validity. An audit trail was maintained to document analytic decisions during data analysis and interpretation. Principal Findings. Psychosocial factors (e.g., attitudes and knowledge, social norms, and perceived control) are identified as determinants of service use, thereby expanding the Andersen model (1995). African-American and white focus group members differed in their reported accessibility of information about long-term care, social norms concerning caregiving expectations and burden, and concerns of privacy and self-determination. Conclusions. More comprehensive identification of psychosocial factors may enhance our understanding of the complex role of race/ethnicity in long-term care use as well as the effectiveness of policies and programs designed to address disparities in long-term care service use among minority and nonminority groups. [source]


Effects of hippocampal cholinergic deafferentation on learning strategy selection in a visible platform version of the water maze

HIPPOCAMPUS, Issue 6 2003
J.L. Bizon
Abstract Recent evidence has suggested that the relative levels of acetylcholine (ACh) between brain structures may be an important factor in the choice of behavioral strategy in settings in which either hippocampal or dorsal striatal brain systems can be employed both effectively and independently (McIntyre and Gold. 1999. Soc Neurosci Abs 25:1388). The current investigation used the neurotoxin 192 IgG-saporin to deplete the hippocampus of ACh selectively, while leaving ACh in other brain regions, including dorsal striatum, intact. Rats were then trained on a version of the Morris water maze, in which behavioral strategies attributed to the hippocampus and dorsal striatum are placed in direct competition. It was predicted that rats with hippocampal ACh depletion would display a cue bias. Contrary to this prediction, depleting hippocampal ACh did not bias against and, in fact, promoted use of a hippocampal place strategy in this task, as indicated by choice in competition tests and performance on hidden platform training trials. These data add to a growing literature demonstrating that the septohippocampal cholinergic system is not required for accurate spatial learning and suggest a complex role for basal forebrain projections in processing information about the spatial environment. © 2003 Wiley-Liss, Inc. [source]


Multidrug resistance 1 gene polymorphism and susceptibility to inflammatory bowel disease

INFLAMMATORY BOWEL DISEASES, Issue 5 2007
S. Ardizzone MD
Abstract Background: Several studies have evaluated the role of the multidrug resistance 1 gene (MDR1) polymorphism, which encodes the membrane-bound efflux transporter P-glycoprotein 170, in determining susceptibility to and disease behavior in inflammatory bowel disease (IBD), but with conflicting results. Methods: A total of 211 patients with Crohn's disease (CD), 97 patients with ulcerative colitis (UC), and 212 control subjects were investigated for the presence of MDR1 G2677T/A and C3435T polymorphisms. Genotype frequencies of CD and UC patients were compared to those observed in a control population. Genotype,phenotype correlations with major clinical features were also established and estimated risks (odds ratio [OR] with 95% confidence interval [CI]) for the mutations were calculated by a logistic regression analysis and multiple correspondent analysis. Results: No significant difference was observed for genotype frequencies for both MDR1 G2677T/A and C3435T polymorphisms on overall disease susceptibility for either CD or UC patients compared with control subjects. A significant association was found between the MDR1 C3435T polymorphism and patients with ileo-colonic CD (OR = 3.34; 95% CI: 1.34,8.27). Interestingly, a negative association was found between MDR1 C3435T polymorphism in patients with a positive family history for IBD (OR = 0.44; 95% CI: 0.20,0.95) and articular manifestations (OR = 0.29; 95% CI: 0.13,0.68). Both susceptible and protective effects were identified. No significant association between G2677T/A polymorphism and any specific subphenotypes was found, nor was there any association with subphenotypic categories of UC and both single nucleotide polymorphisms. Conclusions: The results of our study suggest that MDR1 gene polymorphism could have a role in determining susceptibility to IBD. The variability of this possible effect in the several studies reported so far may be the indirect expression of the complex role played by the MDR1 gene and its product, P-glycoprotein 170, in the regulation of host,bacteria interactions and in the pathogenesis of IBD. (Inflamm Bowel Dis 2007) [source]


Upregulation of miR-23a,27a,24 decreases transforming growth factor-beta-induced tumor-suppressive activities in human hepatocellular carcinoma cells

INTERNATIONAL JOURNAL OF CANCER, Issue 4 2008
Shenglin Huang
Abstract Transforming growth factor-beta (TGF-beta) plays a dual and complex role in human cancer. In this report, we observe a specific set of MicroRNAs (miRNAs) changed in response to TGF-beta in human hepatocellular carcinoma (HCC) cells by miRNA microarray screening. A cluster of miRNA, miR-23a,27a,24, is induced in an early stage by TGF-beta in Huh-7 cells. Knockdown of Smad4, Smad2 or Smad3 expression by RNA interference can attenuate the response of miR-23a,27a,24 to TGF-beta addition, indicating that this induction is dependent on Smad pathway. We also explore that miR-23a,27a,24 can function as an antiapoptotic and proliferation-promoting factor in liver cancer cells. In addition, expression of this miRNA cluster is found to be remarkably upregulated in HCC tissues versus normal liver tissues. These findings suggest a novel, alternative mechanism through which TGF-beta could induce specific miRNA expression to escape from tumor-suppressive response in HCC cells. © 2008 Wiley-Liss, Inc. [source]


From competence to capability: a study of nurse practitioners in clinical practice

JOURNAL OF CLINICAL NURSING, Issue 2 2008
Anne Gardner BA, MRCNA
Aims and objectives., This research aimed to understand the level and scope of practice of the nurse practitioner in Australia and New Zealand further using a capability framework. Background., The original study, from which the present paper was developed, sought to identify competency standards for the extended role of the nurse practitioner in Australia and New Zealand. In doing so the researchers became aware that while competencies described many of the characteristics of the nurse practitioner they did not manage to tell the whole story. In a search of the literature, the concept of capability appeared to provide a potentially useful construct to describe the attributes of the nurse practitioner that went beyond competence. Design., A secondary analysis of data obtained from interviews with nurse practitioners working in Australia and New Zealand was undertaken. These data had previously been obtained in a study to identify nurse practitioner competencies. The analysis described in this paper investigated whether or not the components of capability would adequately explain the characteristics of the nurse practitioner. Methods., Fifteen nurse practitioners were interviewed from Australia and New Zealand. A secondary (deductive) analysis of interview data using capability as a theoretical framework was conducted. Results., The analysis showed that capability and its dimensions is a useful model for describing the advanced level attributes of nurse practitioners. Thus, nurse practitioners described elements of their practice that involved: using their competences in novel and complex situations as well as the familiar; being creative and innovative; knowing how to learn; having a high level of self-efficacy; and working well in teams. Conclusions., This study suggests that both competence and capability need to be considered in understanding the complex role of the nurse practitioner. Relevance to clinical practice., The dimensions of capability need to be considered in the education and evaluation of nurse practitioners. [source]


Preceptors' experiences of clinically educating and assessing undergraduate nursing students: an Irish context

JOURNAL OF NURSING MANAGEMENT, Issue 2 2010
BRIDIE MCCARTHY MSc
mccarthy b. & murphy s. (2010) Journal of Nursing Management 18, 234,244 Preceptors' experiences of clinically educating and assessing undergraduate nursing students: an Irish context Aim, To explore preceptors' views and experiences of preceptoring undergraduate nursing students. Background, Undertaking a preceptoring role is acknowledged internationally as complex and challenging. With the introduction of the undergraduate degree programme in Ireland (2002), preceptors were assigned a more formal role in the teaching and assessing of students. As this was a new programme for students and an additional responsibility for preceptors, it was important to investigate how preceptors found this new experience. Methods, Data were collected using a mixed methods descriptive approach. Results, Many preceptors wanted to become a preceptor and enjoyed the role. The majority of preceptors found the role stressful and burdensome and did not feel adequately supported by their clinical managers. Preceptors expressed the need for protected time, support, feedback and recognition from management for undertaking this role. Conclusion, Findings validate problems experienced with preceptoring in other English-speaking countries and contribute further to building a case for vital change in this component of nursing education and nursing practice. Implications for nursing management, Managers should focus on the challenges expressed by preceptors in this study and identify appropriate strategies to carefully select, monitor and support preceptors in this complex role. [source]


Conducting the symphony: a qualitative study of facilitation in problem-based learning tutorials

MEDICAL EDUCATION, Issue 4 2009
Tracey Papinczak
Context, Tutors in problem-based learning (PBL) tutorials have a complex role to play in facilitating students' learning. This includes providing support for students' acquisition of content knowledge and skills in critical thinking, coaching of group processes and modelling of reflective practice. Few studies which investigate the key role of tutors in the PBL tutorial process are qualitative in design. Methods, This study explores the nature and technique of facilitation provided by PBL tutors from the students' viewpoint. Data were obtained from written responses to an open-ended question asking students about the effectiveness of their PBL tutor(s) and from in-depth interviews carried out with two randomly selected students. Results, Three main themes arose from the inductive analysis of qualitative data: (i) role confusion by tutors; (ii) tutor management of sensitive issues, and (iii) facilitation ,style'. The theme of tutors' facilitation style was dominant and three sub-categories were apparent. These were: (i) managing the learning in PBL tutorials; (ii) facilitating group processes, and (iii) guiding group discussion. Conclusions, Findings highlight the need for tutors to regularly review the PBL tutorial processes and group dynamics within the tutorial setting. These findings have implications for tutor training and programmes of ongoing professional development for PBL facilitators. [source]


Another piece of the puzzle of apoptotic cytochrome c release

MOLECULAR MICROBIOLOGY, Issue 3 2007
Alfons Lawen
Summary Involvement of the mitochondrial permeability transition pore (PTP) in apoptosis and PTP structure are highly controversial. In this issue of Molecular Microbiology, experiments based on yeast genetics analyse the roles of the three proteins commonly considered to form the PTP, i.e. porin, ADP/ATP carrier (ACC) and mitochondrial cyclophilin, on apoptosis-like cell death. Whereas knocking out cyclophilin had no effect, the porin-1 knockout yeast showed enhanced apoptosis, suggesting that porin-1 has an antiapoptotic role. Loss of the ACC proteins afforded protection against some causes of death, but enhanced death induced by H2O2, suggesting a more complex role for the ACC proteins in regulating apoptosis-like death in yeast. [source]


Transient expression of a vacuolar peroxidase increases susceptibility of epidermal barley cells to powdery mildew

MOLECULAR PLANT PATHOLOGY, Issue 6 2001
Brian Kåre Kristensen
summary The expression of genes encoding the peroxidases, Prx7 and Prx8, is induced in barley leaf tissue after inoculation with the barley powdery mildew fungus, Blumeria graminis f.sp. hordei (DC) Speer (Bgh). The role of these peroxidases in general barley defence responses against fungal attack was investigated using a transient expression system. Colonization frequencies of Bgh on cells transfected with Prx7 or Prx8 expression-, mutant- or fusion-DNA constructs were compared to the frequencies on cells expressing a ,-glucuronidase (GUS) control construct. Twice the number of powdery mildew colonies were observed on cells expressing Prx7 as compared to control cells. Introduction of either mutant or truncated versions of Prx7 showed that decreased resistance against Bgh was dependent on the presence of the C-terminal signal peptide required for correct subcellular targeting, but not affected significantly by mutations in the catalytic centre. No impact on Bgh performance was observed after the introduction of Prx8 or mutant constructs. An enhanced accumulation of the apoplastic Prx8 was verified by immunocytology. These results indicate a more complex role of peroxidases in defence responses than was previously suspected. [source]


Immunologic Changes in TNF-alpha, sE-selectin, sP-selectin, sICAM-1, and IL-8 in Pediatric Patients Treated for Psoriasis with the Goeckerman Regimen

PEDIATRIC DERMATOLOGY, Issue 6 2007
Lenka Borska M.D., Ph.D.
The present study investigated changes in the serum levels of proinflammatory cytokines and soluble forms of adhesion molecules in children with psoriasis. The observed patient group of 26 children was treated with the Goeckerman regimen. This therapy combines dermal application of crude coal tar with ultraviolet radiation. The Psoriasis Area Severity Index decreased significantly after treatment by with the Goeckerman regimen (p < 0.001). Serum levels of the proinflammatory cytokine TNF-alpha and adhesion molecules sICAM-1, sP-selectin and sE-selectin decreased after the Goeckerman regimen. The TNF-alpha and sICAM-1 decreased significantly (p < 0.05). Our findings support the complex role of these immune parameters in the immunopathogenesis of psoriasis in children. The serum level of IL-8 increased after the Goeckerman regimen. This fact indicates that the chemokine pathway of IL-8 activity could be modulated by this treatment, most likely by polycyclic aromatic hydrocarbons. [source]


Growth and characterization of bilayer InAs/GaAs quantum dot structures

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 10 2006
B. L. Liang
Abstract One of the difficulties in understanding energy transfer in bilayer quantum dot structures is the complex role of carrier tunneling. This limitation is due to the fact that, for most studies to date, QDs in each layer have only one confined energy level making it difficult to study resonant tunneling effects. In this work, we have investigated the low growth-rate technique to produce dislocation-free very large QDs in the second layer that are characterized by several confined energy levels. The high quality surface morphology and optical behavior of these structures were demonstrated by AFM and PL measurements. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Ascorbic acid, a familiar small molecule intertwined in the response of plants to ozone, pathogens, and the onset of senescence

PLANT CELL & ENVIRONMENT, Issue 8 2004
P. L. CONKLIN
ABSTRACT Ascorbic acid is a well-known antioxidant and cellular reductant with an intimate and complex role in the response of plants to ozone. It is clear from a number of studies that sensitivity to ozone is correlated with total ascorbic acid levels, and that a first line of defence against the reactive oxygen species generated in the apoplastic space by ozone is ascorbic acid. For activity, ascorbic acid must be in the fully reduced state. Therefore, both the rate of ascorbic acid synthesis and recycling via dehydroascorbate and monodehydroascorbate reductases are critical in the maintenance of a high ascorbic acid redox state. Active transport of ascorbic acid across the plasma membrane is necessary to achieve reduction of oxidized ascorbic acid by cytoplasm-localized reductases. It has been known for some time that the chlorotic lesions produced by exposure to ozone are not unlike lesions produced by the hypersensitive response to avirulent pathogen attack. Surprisingly, activation of a defence gene-signalling network by both ozone and pathogens is influenced by the level of ascorbic acid. Indeed, in addition to acting simply as an antioxidant in the apoplastic space, ascorbic acid appears to be involved in a complex phytohormone-mediated signalling network that ties together ozone and pathogen responses and influences the onset of senescence. [source]


,-Aminobutyric acid is present in a spatially discrete subpopulation of hair cells in the crista ampullaris of the toadfish Opsanus tau

THE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2004
Gay R. Holstein
Abstract Although ,-aminobutyric acid (GABA) and glutamate are known to be present in the vestibular sensory epithelia of a variety of species, the functional relationship between these two transmitters is not clear. The present study addresses the three-dimensional spatial distribution of GABA and glutamate immunoreactivity in the vestibular labyrinth of the oyster toadfish by using whole end organs labeled by immunofluorescence with monoclonal anti-GABA and/or antiglutamate antibodies and visualized as whole mounts by multiphoton confocal microscopy. We find glutamate-immunoreactive hair cells present throughout the sensory epithelium. In contrast, prominent GABA immunoreactivity is restricted to a small population of hair cells located in the central region of the crista. Double immunofluorescence reveals two distinct staining patterns in GABA-labeled hair cells. Most (,80%) GABA-labeled cells show trace levels of glutamate, appropriate for the metabolic/synthetic role of cytoplasmic glutamate. The remainder of the GABA-stained cells contain substantial levels of both GABA and glutamate, suggesting transmitter colocalization. In the toadfish utricle, glutamatergic hair cells are present throughout the macula. GABA-immunoreactive hair cells follow the arc of the striola, and most GABA-labeled receptor cells coexpress glutamate. The localization of GABA was explored in other species as well. In the pigeon, GABAergic hair cells are present throughout the crista ampullaris. Our findings demonstrate that multiple, neurochemically distinct types of hair cells are present in vestibular sensory epithelia. These observations, together with the excitatory activity generally associated with 8th nerve afferent fibers, strongly suggest that GABA serves an important, specific, and complex role in determining primary afferent response dynamics. J. Comp. Neurol. 471:1,10, 2004. © 2004 Wiley-Liss, Inc. [source]


Neuropeptide regulators of the juvenile hormone biosynthesis (in vitro) in the beetle, Tenebrio molitor (Coleoptera, Tenebrionidae)

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2010
Mohatmed Abdel-latief
Abstract The genome of Tribolium castaneum encodes two allatostatin [AS type B; W(X)6Wamide and AS type C; PISCF-OH] and one allatotropin (AT) precursor, but no AS type A (FGLamide) (Tribolium Genome Sequencing Consortium, 2008: Nature 452:949,955). Here we studied the activity (in vitro) of peptides derived from these precursors on the synthesis/release of juvenile hormone (JH) III. The corpora cardiaca-corpora allata (CC-CA) complexes of adult females of another tenebrionid beetle, the mealworm Tenebrio molitor, were used. Incubating the gland complexes in a medium containing Trica-AS B3 peptide, we showed that the peptide has allatostatic function in T. molitor. The activity of the type C AS depended on the age of the test animals and their intrinsic rate of JH III biosynthesis. The Trica-AS C peptide inhibited the JH release from CA of 3-day-old females with a high intrinsic rate of JH synthesis, but activated JH release from the CA of 7-day-old females with a lower intrinsic rate of JH production. The allatotropin peptide (Trica-AT) also activated the JH release from the CA of 7-day-old females in a dose-dependent and reversible manner. Unexpectedly, a type A AS derived from the precursor of the American cockroach Periplaneta americana (Peram-AS A2b) inhibited the JH release from the CA of younger and older females in the concentration range of 10,8 to 10,4,M, and the effects were fully reversible in the absence of peptide. These data suggest a complex role of allatoactive neuropeptides in the regulation of JH III biosynthesis in beetles. © 2010 Wiley Periodicals, Inc. [source]


P2X7 and NRAMP1/SLC11 A1 gene polymorphisms in Mexican mestizo patients with pulmonary tuberculosis

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2007
P. Niño-Moreno
Summary Tuberculosis remains one of the most important infectious diseases worldwide. Several studies have suggested that genetic factors may affect susceptibility to tuberculosis, but the specific genes involved have not yet been fully characterized. NRAMP1/SLC11 A1 and P2X7 genes have been linked to increased risk for tuberculosis in some African and Asiatic populations. To explore the potential role of these genes in the susceptibility to pulmonary tuberculosis in a Mexican mestizo population, we evaluated the association of D543N and 3,-UTR polymorphisms in NRAMP1/SLC11 A1 and ,,762 and A1513C polymorphisms in P2X7 genes with the risk for tuberculosis. Polymerase chain reaction (PCR) amplification of genomic DNA followed by restriction fragment length polymorphism analysis, and allelic-specific PCR was employed. We found no significant differences in allelic frequency in NRAMP1/SLC11 A1 gene polymorphisms in 94 patients with tuberculosis compared to 100 healthy contacts. Similarly, no significant association of the P2X7,762 gene polymorphism with tuberculosis was detected. In contrast, the P2X7 A1513C polymorphism was associated significantly with tuberculosis (P = 0·02, odds ratio = 5·28, 95% CI, 0·99,37·69), an association that had not been reported previously. However, when the function of P2X7 was assessed by an l -selectin loss assay, we did not find significant differences in patients compared to healthy contacts or between PPD+ and PPD, control individuals. This study further supports the complex role of P2X7 gene in host regulation of Mycobacterium tuberculosis infection, and demonstrates that different associations of gene polymorphisms and tuberculosis are found in distinct racial populations. [source]


Exposure to violence and aggression: protective roles of social support among urban African American youth

JOURNAL OF COMMUNITY PSYCHOLOGY, Issue 6 2008
Shira Benhorin
This cross-sectional study examined the impact of social support on the relation between exposure to violence and aggressive behavior, as reported by self, peers, and teachers. The main-effects and stress-buffering models of social support were tested for parents, teachers, classmates, and close friends among 127 urban, African American youth. The results demonstrate the negative impact of violence exposure on aggressive behavior and the complex roles of social support in these relations. Specifically, more perceived support from parents, teachers, and close friends was associated with lower teacher-reported aggressive behavior, whereas classmate support buffered the impact of violence on peer-reported aggressive behavior. These findings, multiple reporter differences, and implications for preventive interventions are discussed. © 2008 Wiley Periodicals, Inc. [source]


Roles of nitric oxide, carbon monoxide, and hydrogen sulfide in the regulation of the hypothalamic,pituitary,adrenal axis

JOURNAL OF NEUROCHEMISTRY, Issue 3 2010
Cesare Mancuso
J. Neurochem. (2010) 113, 563,575. Abstract The importance of stress in modifying human behavior and lifestyle is no longer a matter of debate. Although mild stress enhances the immune response and prevents infections, prolonged stress seems to play pathogenic roles in depression and neurodegenerative disorders. The body has developed an adaptive stress response consisting of cardiovascular, metabolic, and psychological changes, which act in concert to eliminate stressors. One of the major components of this response is the hypothalamic,pituitary,adrenal axis, also known as the stress axis. Over the last 30 years, many studies have documented the integrated stress-axis regulation by neurotransmitters. They have also demonstrated that gaseous neuromodulators, such as NO, CO, and H2S, regulate the hypothalamic release of neuropeptides. The specific effects (stimulatory vs. inhibitory) of these gases on the stress axis varies, depending on the type of stress (neurogenic or immuno-inflammatory), its intensity (low or high), and the species studied (rodents or humans). This review examines the complex roles of NO, CO, and H2S in modulation of stress-axis activity, with particular emphasis on the regulatory effects they exert at the hypothalamic level. [source]


Nitric oxide and tissue destruction

ORAL DISEASES, Issue 1 2001
HK Kendall
Nitric oxide (NO) is a free radical which has complex roles in both health and disease. It is now recognized that NO is essential for a vast spectrum of intracellular and extracellular events in a wide variety of tissues. NO has also been implicated in the pathogenesis of numerous inflammatory and autoimmune diseases. In this review we consider the roles of NO generally and in particular the implications for periodontal diseases. [source]


Sociocultural Perceptions and Patterns of Cigarette and Alcohol Use among College Students in Vietnam

ASIAN SOCIAL WORK AND POLICY REVIEW, Issue 3 2008
Paul DuongTran
This empirical study was conducted in the Socialist Republic of Vietnam to investigate cross-sectionally the influences of sociocultural contexts on the patterns of addictive substance use cigarette, alcohol, and illicit drugs. A sample of 202 monolingual adults who were enrolled in college courses at the University of Hanoi in Vietnam responded to a self-reported questionnaire in their native language on the frequency, quantity, and occasions of addictive behavior. The project staff were fluent in English and Vietnamese. The questionnaire was critically reviewed for its face validity and cultural appropriateness before being translated into Vietnamese. In addition to patterns of use, this research explored the central role of drinking alcohol and smoking cigarettes in peer socialization among college adults. Vietnam, like other Asian cultures, emphasizes initiation and conformity to social traditions and norms. The empirical findings provide invaluable knowledge of the complex roles of cigarette and alcohol in the social processes and relationship-building among college adults in Vietnam. Further knowledge will assist in identifying intervention approaches and health prevention that is more focused and congruent with cultural and social beliefs about this behavior and these substances. Its implications for research into culturally appropriate intervention and prevention are also discussed. [source]


"JIP"ing along the axon: the complex roles of JIPs in axonal transport,

BIOESSAYS, Issue 1 2008
Sandhya P. Koushika
JIPs are JNK interacting proteins and bind to JNK cascade kinases. JIP1 and JIP3 were known to be adaptors linking cargo to Kinesin-I, a major molecular motor for axonal transport. Recent research sheds further light on JIPs' complex roles in axonal transport, namely in activation of Kinesin-I and in cargo release. In Drosophila, APLIP1/JIP1 allows the Kinesin-I complex to enable cargo release through activation of JNK signaling.1 In mammalian cell culture, JIP1 is necessary and, together with UNC-76/FEZ1, sufficient for activating Kinesin-I.2 I discuss and compare the many roles played by JIP1 and JIP3 through interactions with several distinct players, in retrograde as well as anterograde transport. BioEssays 30:10,14, 2008. © 2007 Wiley Periodicals, Inc. [source]


Models of Change Agency: a Fourfold Classification

BRITISH JOURNAL OF MANAGEMENT, Issue 2 2003
Raymond Caldwell
Change agents often play significant roles in initiating, managing or implementing change in organizations. Yet these roles are invariably exaggerated or misrepresented by one-dimensional models that ignore the full complexity and scope of change agent roles. Following a review and theoretical clarification of some of the literature and empirical research on change agency, a new fourfold classification of change agents is proposed, covering leadership, management, consultancy, and team models. The four models reaffirm the significance of the multifaceted and complex roles change agents perform in organizational change, while underlining the importance of conceiving change interventions within organizations as processes that need to be coordinated and effectively managed. [source]