bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential Melanin‐Concentrating Hormone Gene Expression in Two Hypothalamic Nuclei of the Teleost Tilapia in Response to Environmental Changes
Authors: Gröneveld Diet , Balm Paul H.M. , Martens Gerard J.M. , Bonga Sjoerd E. Wendelaar 
Published: September 2006

AbstractFor some teleosts, a role has been established for melanin‐concentrating hormone (MCH) background adaptation and stress response. In teleost fishes, prepro‐MCH (ppMCH) rnRNA is expressed in the hypothalamus, predominantly in neurons of the nucleus lateralis tuberis (NLT) and in scattered cells of the nucleus recessus lateralis (NRL). The response of mature tilapia to different environmental challenges was studied by assessing ppMCH rnRNA levels in these two hypothalamic nuclei by quantitative dot blot analysis. Changes in background colour induced pronounced differences in ppMCH mRNA expression in the NLT, but not in the NRL. The NLT of tilapia adapted to a white background contained 2.5 to 3 times more ppMCH mRNA than the NLT of black‐adapted fish. The NLT of fish kept on neutral background contained intermediate levels of ppMCH mRNA, which were significantly lower than the levels in white‐adapted fish. Oral administration of dexamethasone lowered plasma cortisol concentrations, but had no effect on ppMCH mRNA levels in white‐ and black‐adapted fish. In tilapia exposed to strongly acidified water (pH 3.5), plasma cortisol and ACTH concentrations were highly elevated, and plasma chloride concentrations considerably lower than in controls. These fish responded with a 70% rise in ppMCH mRNA levels in the NLT, which is most probably associated with a stress response evoked by inadequate osmoregulation. After exposure to a milder acidification (pH 4.0) or to seawater no significant changes in ppMCH mRNA levels occurred in either the NLT or the NRL, nor in plasma chloride, cortisol and ACTH levels. A specific increase of ppMCH mRNA levels in the NRL was observed in repeatedly disturbed tilapia. We conclude that MCH neurons in the NLT and NRL of this teleost differentially respond to background colour, acidification and disturbance stress, and that this response is not strictly associated with changes in plasma ions and activity of the pituitary‐interrenal axis.
Regulation of Melatonin Secretion by Light in the Isolated Pineal Organ of the White Sucker (Catostomus commersoni)
Authors: Bolliet Valérie , Falcón Jacky , Ali M. Ather 
Published: September 2006

AbstractThe effects of different lighting conditions and physical parameters of light were investigated in the isolated pineal organ of the white sucker kept under static or superfusion culture. The secretion of pineal melatonin is directly controlled by the photoperiod and completely suppressed under constant illumination. When pineal organs are exposed to unexpected light at night, the secretion of melatonin is significantly reduced within 15 min and reaches basal value after 30–35 min of light treatment. The inhibition of melatonin secretion by unexpected light at night depends on the irradiance, duration, timing of the treatment and the lighting history of the pineal organ.
Leukaemia Inhibitory Factor Expression in Cultured Rat Anterior Pituitary is Regulated by Glucocorticoids
Authors: Carter David A. 
Published: September 2006

AbstractLeukaemia inhibitory factor (LIF) is the generally recognized nomenclature for a pleiotropic cytokine that exerts multiple biological effects in different systems. However, its role in the neuroendocrine system is relatively unexplored, with the exception of one report indicating that LIF may act to determine the unique vascular organization of the pituitary gland. In the present study the expression of LIF mRNA has been demonstrated for the first time in the pituitary gland of the rat, in all three pituitary lobes. However, LIF gene expression is restricted to tissues in explant culture where LIF transcripts are readily detectable by Northern Techniques. Similar studies using the reverse transcriptase‐polymerase chain reaction (RT‐PCR) technique also failed to detect LIF transcripts in fresh tissue from adult animals. These results are consistent with the hypothesis that LIF acts to mediate the response to trauma, a response that may include the induction of neuropeptide expression in the anterior pituitary.In further studies it has also been shown that anterior pituitary LIF mRNA is super‐induced in the presence of protein synthesis inhibitors, a response that indicates a role for a labile protein in the attentuation of LIF expression. Both the explantation response, and the response to protein synthesis inhibitory drugs are decreased in the presence of dexamethasone indicating that a glucocorticoid receptor mechanism acts as a general modulatory influence on LIF mRNA levels. These findings are consistent with the presence of multiple regulatory controls on the expression of LIF that serve to restrict its expression to pathological conditions, and indicate that LIF does not participate in normal endocrine physiology.
Comparison of the Number of Vasopressin‐Producing Hypothalamic Neurons in Rats and Humans
Authors: Harding A. J. , Ng J. L. F. , Halliday G. M. , Oliver J. 
Published: September 2006

AbstractThe aim of this study was to assess the number and proportion of vasopressin‐producing neurons in the hypothalamic magnocellular nuclei in rats and humans. Accurate and unbiased neuronal counts were estimated using the optical disector method. Arginine vasopressin‐containing neurons were immunohistochemically visualized in formalin‐fixed tissue sections. The magnocellular neurons were similar in size and morphology in both species. While the human hypothalamus contained significantly more vasopressin‐containing neurons compared with the rat (36‐fold increase), the proportion of vasopressin‐containing neurons between species was similar. In both species, the majority of supraoptic neurons contained vasopressin, however the proportion of vasopressin‐containing neurons in the human paraventricular nucleus was double that of the rat (nearly a 100‐fold increase in number). These results suggest that the paraventricular nucleus contributes significantly to the release of vasopressin from the posterior pituitary in humans, whereas in rats vasopressin is mainly released by supraoptic neurons.
Annual Variations of in vitro GNRH Release by Hypothalamic Explants in Intact and Castrated Male Mink: Relations with LH, FSH and Testosterone Circulating Serum Levels
Authors: Caillol M. , Mondain‐Monval M. , Rossano B. , Solari A. , Martinet L. 
Published: September 2006

AbstractIn mink, a short‐day breeder, testis growth begins in autumn (November), reaches a maximum in February, before matings occur, and decreases from March to very low volumes during spring and summer. To study the effects of season and testosterone feedback on gonadotrophin and GnRH secretion, the annual variations of LH, FSH, testosterone and GnRH were studied in intact and castrated mink. As portal blood sampling raised serious difficulties, an in vitro static incubation system was used for studying GnRH variations. In intact mink, serum LH concentrations did not vary significantly throughout the year, whereas FSH concentrations increased significantly between September and November then decreased to a minimum in January. Testosterone values rose significantly from November to a maximum from January to March, decreased very rapidly thereafter. Castration in November resulted in a significant increase in LH and FSH concentrations which remained higher than the values measured in intact males throughout the year. In long‐term castrated mink, FSH concentrations did not fluctuate during the year, whereas LH concentrations showed an annual variation, with high values in April and August. For the study of in vitro GnRH liberation, medio‐basal hypothalamic explants were incubated in Krebs‐Ringer phosphate buffer for 3 periods of 15 min, and stimulated with copper complexed equimolarly with histidine (Cu/His, 200 pM) and prostaglandin E2 (PGE2, 10 μM). After Cu/His, the release of GnRH was 1 to 4 fold the basal release; after PGE2, the increase was 4–7 fold the basal release. The basal release of GnRH increased significantly between September and October to reach a maximum in November, decreased significantly in December to a minimum in February then increased progressively from May. The release of GnRH stimulated by Cu/His and PGE2 showed the same seasonal variation as the basal release. Castration 8 days before the sacrifice did not alter the release of GnRH, except in December: the release stimulated by PGE2 was then higher in intact than in castrated mink. Taken together, these results indicate that, with an in vitro static incubation system, it is possible to study the annual variations of GnRH release and to correlate these variations with those of serum gonadotrophin and testosterone concentrations. The synthesis and release of GnRH increased slightly from May, under long days, then more rapidly from September, resulting in an increased secretion of FSH in October, responsible for testis recrudescence. The annual pattern of basal and stimulated GnRH release was similar in intact and castrated mink, suggesting a direct effect of the season on the hypothalamus, rather than a negative feedback effect of the testis; however, testosterone seemed to feedback mainly at the pituitary level.
Cyclic‐di‐GMP‐mediated signalling within the σS network of Escherichia coli
Authors: Weber Harald , Pesavento Christina , Possling Alexandra , Tischendorf Gilbert , Hengge Regine 
Published: September 2006

SummaryBis‐(3′−5′)‐cyclic‐di‐guanosine monophosphate (c‐di‐GMP) is a bacterial signalling molecule produced by diguanylate cyclases (DGC, carrying GGDEF domains) and degraded by specific phosphodiesterases (PDE, carrying EAL domains). Neither its full physiological impact nor its effector mechanisms are currently understood. Also, the existence of multiple GGDEF/EAL genes in the genomes of most species raises questions about output specificity and robustness of c‐di‐GMP signalling. Using microarray and gene fusion analyses, we demonstrate that at least five of the 29 GGDEF/EAL genes in Escherichia coli are not only stationary phase‐induced under the control of the general stress response master regulator σS (RpoS), but also exhibit differential control by additional environmental and temporal signals. Two of the corresponding proteins, YdaM (GGDEF only) and YciR (GGDEF + EAL), which in vitro show DGC and PDE activity, respectively, play an antagonistic role in the expression of the biofilm‐associated curli fimbriae. This control occurs at the level of transcription of the curli and cellulose regulator CsgD. Moreover, we show that H‐NS positively affects curli expression by inversely controlling the expression of ydaM and yciR. Furthermore, we demonstrate a temporally fine‐tuned GGDEF cascade in which YdaM controls the expression of another GGDEF protein, YaiC. By genome‐wide microarray analysis, evidence is provided that YdaM and YciR strongly and nearly exclusively control CsgD‐regulated genes. We conclude that specific GGDEF/EAL proteins have very distinct expression patterns, and when present in physiological amounts, can act in a highly precise, non‐global and perhaps microcompartmented manner on a few or even a single specific target(s).
Inward rectification of the AKT2 channel abolished by voltage‐dependent phosphorylation
Authors: Michard Erwan , Dreyer Ingo , Lacombe Benoît , Sentenac Hervé , Thibaud Jean‐Baptiste 
Published: September 2006

SummaryThe Arabidopsis K+ channel AKT2 possesses the remarkable property that its voltage threshold for activation can be either within the physiological range (gating mode 1), or shifted towards considerably more positive voltages (gating mode 2). Gating mode 1 AKT2 channels behave as delayed K+‐selective inward rectifiers; while gating mode 2 AKT2 channels are K+‐selective ‘open leaks’ in the physiological range of membrane potential. In the present study we have investigated modulation of AKT2 current by effectors of phosphatases/kinases in COS cells and Xenopus oocytes. These experiments show that (i) dephosphorylation can result in AKT2 channel silencing; and (ii) phosphorylation by protein kinase A (PKA) favors both recruitment of silenced AKT2 channels and transition from gating mode 1 to gating mode 2. Interestingly, phosphorylation of AKT2 by PKA in COS cells and Xenopus oocytes is favored by hyperpolarization. Two PKA phosphorylation sites (S210 and S329) were pinpointed in the region of the pore inner mouth. The role of these phosphorylation sites in the switch between the two gating modes was assessed by electrophysiological characterization of mutant channels. The molecular aspects of AKT2 regulation by phosphorylation, and the possible physiological meaning of such regulation in the plant context, are discussed.
Tobacco aquaporin NtAQP1 is involved in mesophyll conductance to CO2in vivo
Authors: Flexas Jaume , Ribas‐Carbó Miquel , Hanson David T. , Bota Josefina , Otto Beate , Cifre Josep , McDowell Nate , Medrano Hipólito , Kaldenhoff Ralf 
Published: September 2006

SummaryLeaf mesophyll conductance to CO2 (gm) has been recognized to be finite and variable, rapidly adapting to environmental conditions. The physiological basis for fast changes in gm is poorly understood, but current reports suggest the involvement of protein‐facilitated CO2 diffusion across cell membranes. A good candidate for this could be the Nicotiana tabacum L. aquaporin NtAQP1, which was shown to increase membrane permeability to CO2 in Xenopus oocytes. The objective of the present work was to evaluate its effect on the in vivo mesophyll conductance to CO2, using plants either deficient in or overexpressing NtAQP1. Antisense plants deficient in NtAQP1 (AS) and NtAQP1 overexpressing tobacco plants (O) were compared with their respective wild‐type (WT) genotypes (CAS and CO). Plants grown under optimum conditions showed different photosynthetic rates at saturating light, with a decrease of 13% in AS and an increase of 20% in O, compared with their respective controls. CO2 response curves of photosynthesis also showed significant differences among genotypes. However, in vitro analysis demonstrated that these differences could not be attributed to alterations in Rubisco activity or ribulose‐1,5‐bisphosphate content. Analyses of chlorophyll fluorescence and on‐line 13C discrimination indicated that the observed differences in net photosynthesis (AN) among genotypes were due to different leaf mesophyll conductances to CO2, which was estimated to be 30% lower in AS and 20% higher in O compared with their respective WT. These results provide evidence for the in vivo involvement of aquaporin NtAQP1 in mesophyll conductance to CO2.
The maize Mucronate mutation is a deletion in the 16‐kDa γ‐zein gene that induces the unfolded protein response1
Authors: Kim Cheol Soo , Gibbon Bryan C. , Gillikin Jeffrey W. , Larkins Brian A. , Boston Rebecca S. , Jung Rudolf 
Published: September 2006

Summary Mucronate (Mc) was identified as a dominant maize (Zea mays L.) opaque kernel mutation that alters zein storage protein synthesis. Zein protein bodies in Mc endosperm are misshapen and are associated with increased levels of ER Lumenal Binding Protein (BiP). Using GeneCallingTM to profile endosperm RNA transcripts, we identified an aberrant RNA in Mc that encodes the 16‐kDa γ‐zein protein. The transcript contains a 38‐bp deletion (nucleotides 406–444 after the initiation codon) that creates a frame‐shift mutation and an abnormal sequence for the last 63 amino acids. Genetic mapping revealed the Mc mutation is linked with the locus encoding the 16‐kDa γ‐zein, and two‐dimensional gel electrophoresis confirmed the 16‐kDa γ‐zein protein is altered in Mc. The mutant protein exhibited changes in solubility properties and co‐immunoprecipitated with the molecular chaperone, BiP. Transgenic maize plants expressing the Mc 16‐kDa γ‐zein manifested an opaque kernel phenotype with enhanced levels of BiP in the endosperm, similar to the Mc mutant. Unlike the wild‐type protein, the Mc 16‐kDa γ‐zein interacted only weakly with the 22‐kDa α‐zein when expressed in the yeast two‐hybrid system. These results indicate that the Mc phenotype results from a frame‐shift mutation in the gene encoding the 16‐kDa γ‐zein protein, leading to the unfolded protein response in developing endosperm.
The efficacy of photochemical treatment with methylene blue and light for the reduction ofTrypanosoma cruziin infected plasma
Authors: Gironés N. , Bueno J. L. , Carrión J. , Fresno M. , Castro E. 
Published: September 2006

Background and Objectives Chagas disease is a transfusion‐transmitted infection. This study evaluates the efficacy of a methylene blue (MB) and light system for reducing the viability ofTrypanosoma cruziin plasma.Materials and Methods Trypanosoma cruzistrains were spiked in plasma pools. Treatment arms included combined filtration, MB, light and freezing. Post‐treatment parasite viability was assayed throughin vitrocultures andin vivoinoculation in inducible nitric oxide synthase‐ and interferon‐γ‐receptor‐deficient mice.Results The filtration, MB and light combined treatment showed a log reduction of > 3·4 inin vitrocultures, and log reductions that ranged from > 4·9 to > 5·8 in deficient mice inoculated with differentT. cruzistrains.Conclusion The treatment of plasma units with the MB and light system reduces theT. cruziburden and could be useful in preventing transfusion‐transmitted Chagas disease.
Ultrastruktur‐Merkmale zur Definition der Begriffe ‘Hefezelle’, ‘Pseudomyzel’ und ‘echtes Myzel’ bei Candida albicans
Authors: Müller J. , Melchinger W. 
Published: September 2006

ZusammenfassungDie Unterscheidung der Gestaltformen ‘Hefezelle’, ‘Pseudomyzel’ und ‘echtes Myzel’ ist in der mykologischen und histopathologischen Diagnostik von Candida albicans‐Mykosen unverzichtbar. Präzise definierte Unterscheidungskriterien fehlen allerdings in der medizinisch‐mykologischen Literatur. Diese Kriterien, basierend auf elektronenmikroskopischen Studien der Zellwand, werden nachfolgend beschrieben.
Upper extremity arteriovenous fistula does not affect pulse oximetry readings
Authors: AVITSIAN RAFI , ABDELMALAK BASEM , SAAD SAMEH , XU MENG , O’HARA JEROME 
Published: September 2006

SUMMARY:Aim:  Arteriovenous fistula (AVF) is usually surgically created in a patient’s upper extremity to provide adequate blood flow during haemodialysis. Blood flow distal to an AVF is altered and theoretically could change pulse oximetry (SpO2) reading, systemic blood pressure and skin temperature. The authors conducted a prospective case–control study to measure changes in these parameters in the upper extremity of patients who have had an AVF.Methods:  In patients with an upper extremity AVF, the authors conducted a prospective case–control study using the patient’s own non‐AVF upper extremity as the control. The authors evaluated other factors that may have influenced blood flow changes distal to an AV fistula like gender, presence of AVF aneurysm, peripheral vascular disease, diabetes mellitus and vasodilator therapy.Results:  Thirty patients were enrolled, skin temperature and blood pressure were significantly altered in the hand distal to the AVF, but there was no significant change in the SpO2.Conclusion:  An upper extremity AVF alters blood pressure and temperature measurements when compared with the contralateral non‐AVF side, but there is no difference in SpO2 provided an adequate signal quality is detected.
Regional citrate anticoagulation in continuous venovenous haemofiltration using commercial preparations
Authors: MUNJAL SANDEEP , EJAZ A AHSAN 
Published: September 2006

SUMMARY:Aim:  The aim of the present study was to test the feasibility of using commercial preparations of replacement and citrate anticoagulation solution in continuous venovenous haemofiltration (CVVH) in a safe, efficient and simple manner.Methods:  Retrospective review of the database of a large continuous renal replacement therapy programme that uses a standardized prescription of high ultrafiltrate CVVH with commercial solutions for replacement fluid and regional citrate anticoagulation was performed.Results:  Records of 28 patients who underwent 91 CVVH sessions were analysed. Median circuit survival time was 37 (59.5–15.5) h and the 48 h survival probability was 40%. Bleeding or metabolic complications were not noted, and the procedure was simple to administer.Conclusion:  Continuous venovenous haemofiltration using commercial preparations of replacement fluid and citrate anticoagulation can be safe, efficient and simple.
High glucose and advanced glycosylated end‐products affect the expression of α‐actinin‐4 in glomerular epithelial cells
Authors: HA TAE‐SUN 
Published: September 2006

SUMMARY:Aim:  To investigate the molecular basis for the phenotypic alterations of glomerular epithelial cells (GEpC, podocytes), involving cytoskeletal changes especially on α‐actinin‐4 as a candidate regulating the barrier to protein filtration and the podocyte actin cytoskeleton.Methods:  To examine the effects of glucose and advanced glycosylated end‐products (AGE) on α‐actinin‐4, the author cultured rat GEpC on AGE‐ or BSA‐coated plates under normal (5 mmol) and high glucose (30 mmol) conditions and examined the distribution of α‐actinin by confocal microscope and measured the change in α‐actinin‐4 production by western blotting and reverse transcription–polymerase chain reaction.Results:  Confocal microscopy indicated that α‐actinin‐4 moved from the peripheral cytoplasm to inner actin filament complexes in the presence of AGE and high glucose. These changes might be related to the fusion of microvilli of cell surface examined by electron microscopy. In western blot analysis, AGE significantly decreased the amount of α‐actinin by 28.1%. Furthermore, the combination of high glucose and AGE decreased the amount of α‐actinin more significantly by 53.6% compared with that of the control. The mRNA expression for α‐actinin‐4 was not changed with high glucose or AGE‐coated surfaces; however, when added, the combination of high glucose and AGE significantly decreased the expression of α‐actinin‐4 mRNA by 15.7% compared with that of the control.Conclusion:  The author suggests that both high glucose and AGE (either individually or in combination) induce the cytoplasmic translocation and the combination suppresses the production of α‐actinin‐4 at the transcriptional level with post‐translational modification and these in vitro changes may explain the cytoskeletal changes of GEpC in diabetic conditions.