bluuebunny/crossref_metadata_2025 huggingface dataset:
Isoprene prevents the negative consequences of high temperature stress in Platanus orientalis leaves
Authors: Velikova Violeta , Loreto Francesco , Tsonev Tsonko , Brilli Federico , Edreva Aglika
Published: October 2006

The phenomenon of enhanced plant thermotolerance by isoprene was studied in leaves of the same age of 1- or 2-year-old Platanus orientalis plants. Our goals were to determine whether the isoprene emission depends on the age of the plant, and whether different emission rates can influence heat resistance in plants of different age. Two-year-old plants emit greater amounts of isoprene and possess better capacity to cope with heat stress than 1-year-old plants. After a high temperature treatment (38°C for 4 h), photosynthetic activity, hydrogen peroxide content, lipid peroxidation and antiradical activity were preserved in isoprene emitting leaves of 1- and 2-year-old plants. However, heat inhibited photosynthesis and PSII efficiency, caused accumulation of H2O2, and increased all indices of membrane damage and antioxidant capacity in leaves of plants of both ages in which isoprene was inhibited by fosmidomycin. In isoprene-inhibited leaves fumigated with exogenous isoprene during the heat treatment, the negative effects on photosynthetic capacity were reduced. These results further support the notion that isoprene plays an important role in protecting photosynthesis against damage at high temperature. It is suggested that isoprene is an important compound of the non-enzymatic defence of plants against thermal stress, possibly contributing to scavenging of reactive oxygen species (ROS) and membrane stabilising capacity, especially in developed plants.
Different radiological findings with the same pathologic diagnosis due to different age in primary osteosarcoma
Authors: Lee S. Y. , Cho W. H. , Song W. S. , Park J. H.
Published: October 2006

Purpose: To examine the imaging characteristics of osteoblastic osteosarcoma in older patients, we compared them with those in adolescents because the radiological features of osteosarcoma can be atypical in elderly patients.

Material and Methods: 29 cases of adolescent patients and 12 patients older than 40 years of age were reviewed. All cases were pathologically confirmed as osteoblastic osteosarcoma. The comparative factors were tumor location, plain radiological features including periosteal reactions, and the degree of soft tissue mass with magnetic resonance (MR) imaging.

Results: Older patients demonstrated frequent osteolytic findings (83.3%), and none of the tumors showed a significant major periosteal reaction. Seven (58.3%) of the 12 tumors had no soft tissue mass (grade 0) and only three (25%) had a grade 3 mass. The differences in the two groups were statistically significant ( P<0.001).

Conclusion: In older patients, primary osteosarcoma should be considered when making a differential diagnosis of osteolytic lesions without any periosteal reactions and small soft-tissue extensions. In cases with atypical findings, the morphology of specimens (aspiration, core, or surgical biopsy) from the lesion should be recommended when making an accurate diagnosis.
HIV-related bronchopulmonary infection by pseudomonas aeruginosa in the HAART era: radiological findings
Authors: Busi Rizzi E. , Schininà V. , Bordi E. , Buontempo G. , Narciso P. , Bibbolino C.
Published: October 2006

Purpose: To evaluate whether highly active antiretroviral therapy (HAART) modifies radiographic appearances of Pseudomonas aeruginosa bronchopulmonary infection in HIV-infected patients. P. aeruginosa is increasingly reported as a respiratory pathogen in HIV+ patients with very low levels of CD4 lymphocytes. Few studies have analyzed the radiological presentation of bronchopulmonary disease that occurs in HAART-treated patients.

Material and Methods: We retrospectively reviewed the chest radiographs of 46 HIV-infected patients with bronchopulmonary diseases in which P. aeruginosa was the sole respiratory pathogen that was isolated. All cases were community-acquired infection. Twenty-four of the patients were on HAART treatment, and 22 were not. Chest radiographs were assessed for the presence and distribution of parenchymal consolidation, reticular or reticulonodular infiltrates, bronchial wall thickening, ground-glass opacities, cavitation, pleural effusion, and adenopathies. Statistical analysis was done using Epi-Info version 6 (CDC, Atlanta, GA, USA).

Results: Normal chest radiographs were observed in 11 patients. Eight of these 11 (73%) were receiving HAART, and 3/11 (27%) were not. The most common radiographic abnormality was bronchopneumonia, present in 24 of 46 patients (52%): in 10 of 24 (42%) patients with HAART and 14 of 22 (64%) without. Cavitation was seen in 1 of 24 (4%) patients with HAART and in 5 of 22 (23%) without HAART.

Conclusion: Cavitation was more frequent in patients that were not receiving HAART, and normal chest radiographs were more frequently seen in patients on HAART.
A second radioisotope injection enhances intraoperative sentinel node identification in breast cancer patients without visualized nodes on preoperative lymphoscintigraphy
Authors: Leikola J. P. , Leppänen E. A. , von Smitten K. A. J. , Leidenius M. H. K.
Published: October 2006

Purpose: To evaluate the influence of a second radioisotope injection on the intraoperative success rate in patients with non-visualized axillary sentinel nodes (SN).

Material and Methods: Altogether, 534 consecutive breast cancer patients with lymphoscintigraphy (LS) and SN biopsy and were included. An intratumoral injection of 99mTc-labeled human albumin colloid with a median dose of 93 MBq was applied. Forty-two of the 80 patients without axillary hot spots on LS received a second tracer injection with a median dose of 70 MBq.

Results: The visualization rate of axillary SN was 454/534 (85%). The intraoperative SN identification rate was 97% in patients with and 69% in patients without visualized SN in the axilla ( P<0.00005), but the success rate was higher (88%) with a second radioisotope injection than without it (47%; P<0.0002).

Conclusion: The failure rate in intraoperative SN identification was minimized using a second radioisotope injection in patients without axillary SN on LS.
A simplified method for continuous hepatic arterial port-catheter system placement not requiring catheter end-hole occlusion
Authors: Yamagami T. , Kato T. , Hirota T. , Yoshimatsu R. , Matsumoto T. , Nishimura T.
Published: October 2006

Purpose: To evaluate the efficacy of hepatic port-catheter system placement without distal catheter tip occlusion or gastroduodenal artery embolization distal to the catheter tip.

Material and Methods: A port-catheter system was percutaneously implanted in 29 patients (16 men, 13 women; mean age 65.6 years) with unresectable liver cancer. Persistent blood flow through the end hole of the catheter was verified immediately and 1–10 days after catheter placement.

Results: In all cases, percutaneous port-catheter placement was successfully performed. In seven of 29 (24.1%) patients, flow through the end hole of the catheter was verified immediately after the procedure. However, no flow was seen 1–10 days after the procedure.

Conclusion: It is not necessary to occlude the end hole of the catheter tip and embolize the gastroduodenal artery beyond the catheter tip when placing a port-catheter system for repeated hepatic arterial infusion chemotherapy.
Politics, history & problems of humanitarian assistance in Sudan
Authors: Middleton Neil , O'keefe Phil
Published: October 2006

It is increasingly widely recognised that humanitarian assistance is broadly understood in two distinct ways: one is to see it as a part of foreign policy, which is the customary position of donating states; the other is to see it as independent of governments and a matter of relieving suffering without distinction and is embodied in the Fundamental Principles of the Red Cross/ Red Crescent family. The present authors argue that any intervention is necessarily a political event and they support this contention with an examination of assistance in Sudan in general and Darfur in particular. In describing the way in which donating states concentrated on the settlement between Khartoum and south Sudan to the detriment of intervention in Darfur in time to forestall massive human slaughter, the authors are pointing to political failure. They also maintain that the consequence of not recognising and examining the political nature of humanitarian assistance is to reduce people affected by emergencies of all kinds to the status of victim, which deprives them of the ability to be the principal agents of their own recovery.
Sustained Notch signaling in progenitors is required for sequential emergence of distinct cell lineages during organogenesis
Authors: Zhu Xiaoyan , Zhang Jie , Tollkuhn Jessica , Ohsawa Ryosuke , Bresnick Emery H. , Guillemot François , Kageyama Ryoichiro , Rosenfeld Michael G.
Published: October 2006

Mammalian organogenesis results from the concerted actions of signaling pathways in progenitor cells that induce a hierarchy of regulated transcription factors critical for organ and cell type determination. Here we demonstrate that sustained Notch activity is required for the temporal maintenance of specific cohorts of proliferating progenitors, which underlies the ability to specify late-arising cell lineages during pituitary organogenesis. Conditional deletion of Rbp-J, which encodes the major mediator of the Notch pathway, leads to premature differentiation of progenitor cells, a phenotype recapitulated by loss of the basic helix-loop-helix (bHLH) factor Hes1, as well as a conversion of the late (Pit1) lineage into the early (corticotrope) lineage. Notch signaling is required for maintaining expression of the tissue-specific paired-like homeodomain transcription factor, Prop1, which is required for generation of the Pit1 lineage. Attenuation of Notch signaling is necessary for terminal differentiation in post-mitotic Pit1+ cells, and the Notch-repressed Pit1 target gene, Math3, is specifically required for maturation and proliferation of the GH-producing somatotrope. Thus, sustained Notch signaling in progenitor cells is required to prevent conversion of the late-arising cell lineages to early-born cell lineages, permitting specification of diverse cell types, a strategy likely to be widely used in mammalian organogenesis.
Retrieval failure versus memory loss in experimental amnesia: Definitions and processes
Authors: Miller Ralph R. , Matzel Louis D.
Published: October 2006

For at least 40 years, there has been a recurring argument concerning the nature of experimental amnesia, with one side arguing that amnesic treatments interfere with the formation of enduring memories and the other side arguing that these treatments interfere with the expression of memories that were effectively encoded. The argument appears to stem from a combination of (1) unclear definitions and (2) real differences in the theoretical vantages that underlie the interpretation of relevant data. Here we speak to how the field might avoid arguments that are definitional in nature and how various hypotheses fare in light of published data. Existing but often overlooked data favor very rapid (milliseconds) synaptic consolidation, with experimental amnesia reflecting, at least in part, deficits in retrieval rather than in the initial storage of information.
Reconsolidation: A brief history, a retrieval view, and some recent issues
Authors: Riccio David C. , Millin Paula M. , Bogart Adam R.
Published: October 2006

This review briefly traces some of the history of the phenomenon of what has come to be called “reconsolidation.” The early findings of retrograde amnesia for an old but reactivated memory led to several interesting but largely behaviorally oriented studies. With only a few sporadic exceptions, research in the area languished until about 2000, when several articles caught the attention of the neuroscience community and led to a number of studies examining the phenomenon at several different levels of analysis. We consider several of the current issues generated by those studies, present a retrieval based model that may account for some findings, and indicate some possible new directions on this topic.
Opioid modulation of Fos protein expression and olfactory circuitry plays a pivotal role in what neonates remember
Authors: Roth Tania L. , Moriceau Stephanie , Sullivan Regina M.
Published: October 2006

Paradoxically, fear conditioning (odor–0.5 mA shock) yields a learned odor preference in the neonate, presumably due to a unique learning and memory circuit that does not include apparent amygdala participation. Post-training opioid antagonism with naltrexone (NTX) blocks consolidation of this odor preference and instead yields memory of a learned odor aversion. Here we characterize the neural circuitry underlying this switch during memory consolidation. Experiment 1 assessed post-training opioid modulation of Fos protein expression within olfactory circuitry (olfactory bulb, piriform cortex, amygdala). Odor–shock conditioning with no post-training treatment (odor preference) induced significant changes in Fos protein expression in the granule cell layer of the olfactory bulb and anterior piriform cortex. Post-training opioid receptor antagonism (odor aversion) prevented the learning-induced changes in the anterior piriform cortex and also induced significant changes in Fos protein expression in the central nucleus of the amygdala. Experiment 2 assessed intra-amygdala opioid modulation of neonate memory consolidation. Post-training infusion of NTX within the amygdala permitted consolidation of an odor aversion, while vehicle-infused pups continued to demonstrate an odor preference. Overall, results demonstrate that opioids modulate memory consolidation in the neonate via modulating Fos protein expression in olfactory circuitry. Furthermore, these results suggest that opioids are instrumental in suppressing neonate fear behavior via modulating the amygdala.
Context and occasion setting in Drosophila visual learning
Authors: Brembs Björn , Wiener Jan
Published: October 2006

In a permanently changing environment, it is by no means an easy task to distinguish potentially important events from negligible ones. Yet, to survive, every animal has to continuously face that challenge. How does the brain accomplish this feat? Building on previous work in Drosophila melanogaster visual learning, we have developed an experimental methodology in which combinations of visual stimuli (colors and patterns) can be arranged such that the same stimuli can either be directly predictive, indirectly predictive, or nonpredictive of punishment. Varying this relationship, we found that wild-type flies can establish different memory templates for the same contextual color cues. The colors can either leave no trace in the pattern memory template, leading to context-independent pattern memory (context generalization), or be learned as a higher-order cue indicating the nature of the pattern-heat contingency leading to context-dependent memory (occasion setting) or serve as a conditioned stimulus predicting the punishment directly (simple conditioning). In transgenic flies with compromised mushroom-body function, the sensitivity to these subtle variations is altered. Our methodology constitutes a new concept for designing learning experiments. Our findings suggest that the insect mushroom bodies stabilize visual memories against context changes and are not required for cognition-like higher-order learning.
Fading in
Authors: Nader Karim , Wang Szu-Han
Published: October 2006

Patient H.M. can form new memories and maintain them for a few seconds before they fade away. From a neurobiological perspective, this amnesia is usually attributed to the absence of memory consolidation, that is, memory storage. An alternative view holds that this impairment reflects that the memory is present but cannot be retrieved. This debate has been unresolved for decades. Here, we will consider some of the arguments that make it so difficult to resolve this issue. In addition, some recent work will be discussed that has gone beyond the shortcomings of previous experimental approaches to strongly suggest that amnesia can be due to a retrieval impairment that can be overcome with a reminder—an example of memories fading in. Finally, this review will suggest some strategies for resolving this debate.
Packing Capillary Columns for RP-HPLC
Authors: Moritz Robert
Published: October 2006

INTRODUCTION

Capillary or microcolumn (<0.5-mm internal diameter [I.D.]) high-performance liquid chromatography (HPLC) is an extremely powerful technique for separating small quantities of proteins and peptides. This protocol describes a procedure for adapting conventional HPLC systems to provide accurate low-flow rates (0.4-4 μl/min) and gradients required to operate slurry-packed capillary columns. A key component of this system is a commercial axial-beam longitudinal flow cell that can be fitted to a number of commercial UV detectors. Procedures are described for the fabrication of 0.32-mm I.D. polyimide-coated fused-silica columns, slurry-packed with reversed-phase chromatographic supports.
Using FLAG Epitope-Tagged Proteins for Coimmunoprecipitation of Interacting Proteins: Figure 1.
Authors: Verhagen Anne
Published: October 2006

INTRODUCTION

This protocol describes the use of FLAG-epitope-tagged proteins for both small-scale analysis and large-scale coimmunoprecipitation of interacting proteins. When examining protein interactions, it is sometimes possible to immunoprecipitate an endogenous protein X directly, without using an epitope tag, if antibodies are available. The advantage of examining interactions of endogenously expressed proteins is that these are more likely to be physiological and less likely to be an artifact of overexpression. However, when scaling up the procedure for protein isolation and identification, epitope-tagged overexpressed protein X (e.g., FLAG-protein X) may be necessary for sufficient coimmunoprecipitating protein to be isolated.
Preparation of Eukaryotic Lysates for 2D Gel Electrophoresis
Authors: Ji Hong
Published: October 2006

INTRODUCTION

Cultured mammalian cell lines are widely used as study models in biomedical research. The protocol described here has been used successfully for many human colon carcinoma cell lines and fibroblast cell lines. Although most cellular proteins can be extracted by this protocol, some DNA-binding proteins may not be recovered. If DNA-binding proteins are to be studied, a nuclease (e.g., Benzonase) should be included. Expression proteomic studies frequently require the detection of low-abundance proteins.
Radioisotopic Labeling of Eukaryotic Cell Proteins Using 35S
Authors: Ji Hong
Published: October 2006

INTRODUCTION

Radioisotope labeling of proteins is an important technique in expression proteomics studies for detecting low-abundance proteins. The procedure given below describes 35S labeling. After the labeling procedure described here, cell lysates can be prepared for analysis by 2D gel electrophoresis.
Radioisotopic Labeling of Eukaryotic Cell Proteins Using 32P
Authors: Ji Hong
Published: October 2006

INTRODUCTION

Radioisotope labeling of proteins is an important technique in expression proteomics studies for detecting low-abundance proteins. The procedure given below describes a labeling technique using 32P labeling. After the labeling procedure described here, cell lysates can be prepared for analysis by 2D gel electrophoresis.
Children at the Centre? The Childcare Act 2006
Authors: Linsey Alison , McAuliffe Ann‐Marie
Published: October 2006

The Childcare Act 2006 is the first piece of legislation of its kind in the UK, and is a significant development for the early years sector and childcare services more broadly. Ensuring every child has the best start in life is one of the guiding principles of the Government's 10‐year strategy for childcare, but the strategies for implementation do not always appear to place the child so firmly at the centre. The childcare agenda is primarily focused on the needs of parents and families to respond to changing working patterns and balancing work and family life.
mlo‐based powdery mildew immunity: silver bullet or simply non‐host resistance?
Authors: HUMPHRY MATT , CONSONNI CHIARA , PANSTRUGA RALPH
Published: October 2006

Durability and effectiveness against all genetic variants of a microbial species are hallmarks of so‐called plant ‘non‐host’ resistance. Highly effective immunity of monocotyledonous barley against the fungal powdery mildew pathogen, which is conferred by loss‐of‐function mutant alleles of the barley Mlo locus, likewise is a durable and broad‐spectrum type of resistance. Although this was long considered as being a barley‐specific phenomenon, recent findings indicate that mlo resistance can also occur in the distantly related dicotyledonous species Arabidopsis thaliana. Shared histological and phytopathological characteristics plus a conserved requirement for a set of genes in Arabidopsis mlo and non‐host powdery mildew resistance indicate a potential common mechanism for these two seemingly distinct types of immunity.
Early exposure to dichlorodiphenyldichloroethylene, breastfeeding and asthma at age six
Authors: Sunyer J. , Torrent M. , Garcia‐Esteban R. , Ribas‐Fitó N. , Carrizo D. , Romieu I. , Antó J. M. , Grimalt J. O.
Published: October 2006

Our aims were to assess association of dichlorodiphenyldichloroethylene (DDE) with childhood asthma measured up to age 6 and the effect of DDE on the protective effect of breastfeeding on asthma. In addition, we attempted to assess the relevant time‐window of DDE exposure (i.e. at birth or at 4 years).

All women presenting for antenatal care in Menorca, Spain over a 12‐month period beginning in mid‐1997 were invited to take part in a longitudinal study that included a yearly visit. Four hundred eighty‐two children were enrolled and 462 provided complete outcome data after 6.5 years of follow‐up. Organochlorine compounds were measured in cord serum of 402 (83%) infants and in blood samples of 285 children aged 4. We defined asthma as the presence of wheezing at age 6 and during any preceding year or doctor‐diagnosed asthma, and used skin prick test at age 6 to determine atopic status.

Results At birth and 4 years of age, all children had detectable levels of DDE (median 1 ng/mL and 0.8 ng/mL, respectively). From birth to age 4, the mean DDE level among children with artificial feeding decreased by 72%, while among breastfed children it increased by 53%. Diagnosed asthma and persistent wheezing were associated with DDE at birth [odds ratio (OR) for an increase in 1 ng/mL, OR=1.18, 95% confidence interval (95% CI)=1.01–1.39 and OR=1.13, 95% CI=0.98–1.30, respectively], but not with DDE at 4 years. Neither breastfeeding nor atopy modified these associations (P>0.3). Breastfeeding protected against diagnosed asthma (OR=0.33, 95% CI=0.08–0.87) and wheezing (OR=0.53, 95% CI=0.34–0.82) in children with low and high DDE levels at birth.

Conclusion In a community without known dichlorodiphenyltrichloroethane environmental releases, this study strengthens the evidence for an effect of DDE on asthma by measuring the disease at age 6 and does not support the hypothesis that DDE modifies the protective effect of breastfeeding on asthma.
Synergistic effects of fluticasone propionate and salmeterol on inhibiting rhinovirus‐induced epithelial production of remodelling‐associated growth factors
Authors: Volonaki E. , Psarras S. , Xepapadaki P. , Psomali D. , Gourgiotis D. , Papadopoulos N. G.
Published: October 2006

Background
Rhinoviruses (RV), the major trigger of acute asthma exacerbations, are able to infect bronchial epithelium and induce production of pro‐inflammatory, but also angiogenic and pro‐fibrotic mediators. Fluticasone propionate (FP) and salmeterol (S) are clinically effective and act synergistically in controlling persistent asthma; however, their effect on virus‐associated asthma is less clear.

Aim
The aim of this study was to assess the individual and combined effects of FP and S on RV‐induced epithelial production of vascular endothelial growth factor (VEGF) and fibroblast growth factor‐2 (FGF‐2).

Methods
Bronchial epithelial cells (BEAS‐2B) were exposed in vitro to RV and were subsequently treated with FP and S, at physiologically relevant concentrations, alone or in combination. VEGF and FGF‐2 were measured in the supernatants of these cultures using ELISA.

Results
FP was able to reduce RV‐induced VEGF production in a dose‐dependent manner. S also induced a smaller reduction; addition of both factors inhibited VEGF synergistically. FGF‐2 production was not inhibited by either FP or S alone, but was significantly reduced when both substances were present in the culture.

Conclusion
This study demonstrates that FP and S may synergistically inhibit the production of angiogenic and/or pro‐fibrotic factors that are induced after RV infection of BEAS‐2B and are implicated in airway remodelling, suggesting that this combination may represent an important therapeutic option on virus‐induced asthma.
Defining the T cell antigen proteome of wasp venom
Authors: Aslam A. , Kessler B. , Batycka M. , O'Callaghan C. A. , Misbah S. A. , Warrell D. A. , Ogg G.
Published: October 2006

Background
While modulation of T cell function is believed to be important in the successful acquisition of clinical tolerance during venom immunotherapy, little is known of the role of wasp venom specific T cell antigens.

Objective
We sought comprehensively to characterize the T cell proteome for wasp venom to facilitate the future development of T cell‐based immunotherapeutic approaches.

Methods
Using peripheral blood mononuclear cells from wasp venom‐allergic individuals and IL‐4 ELISPOT analysis, we characterized T cell responses to whole venom and gel filtration/ion exchange‐fractionated venom. Reactive fractions were purified and identified using highly sensitive electrospray ion‐trap mass spectrometry.

Results
Wasp venom‐allergic individuals have detectable whole wasp venom‐specific T cells directly ex vivo, which show rapid IL‐4 effector function. T cell responses to gel filtration/ion exchange fractionated venom were dominated by responses to phospholipase A1, hyaluronidase and antigen 5.

Conclusion
Although it is likely that there are many T cell antigens within wasp venom, the main responses are to proteins coincident with the known IgE‐binding proteins.
Vasoactive Intestinal Polypeptide mRNA and Peptide Levels are Decreased in the Anterior Pituitary of the Human Growth Hormone‐Releasing Hormone Transgenic Mouse
Authors: Hyde James F. , Morrison David G. , Drake Karen W. , Moore Joseph P. , Maley Bruce E.
Published: October 2006

We recently reported that galanin gene expression is markedly increased in the hyperplastic anterior pituitary gland of the human growth hormone‐releasing hormone (hGHRH) transgenic mouse. To determine if another pituitary peptide hormone with putative growth‐promoting activity is similarly affected, or if this effect is specific to the peptide galanin, we examined vasoactive intestinal polypeptide (VIP) gene expression in the hypothalamic‐pituitary axis of male hGHRH transgenic and non‐transgenic mice. The objectives were to: 1) assess VIP peptide concentrations, 2) estimate relative differences in VIP mRNA levels, 3) determine the effects of acute treatment with 17(3‐estradiol on VIP peptide and mRNA levels, and 4) quantify the density of immunoreactive VIP pituitary cells by immunohistochemistry. Four to five month old male hGHRH transgenic mice and their non‐transgenic siblings were identified by PCR. Immunoreactive VIP concentrations were decreased by 50% in the anterior pituitary glands of hGHRH transgenic mice as compared to non‐transgenic siblings. In contrast, no differences in immunoreactive VIP concentrations were observed in the hypothalamus or frontal cerebral cortex of transgenic and non‐transgenic mice. Treatment with 17β‐estradiol significantly increased VIP concentrations in the anterior pituitary gland of both transgenic and non‐transgenic mice; however, VIP peptide concentrations in the anterior pituitary glands of hGHRH transgenic mice remained 50% lower. Relative differences in VIP mRNA levels were estimated by RT‐PCR, and were found to be 2.5‐fold higher in the anterior pituitary glands of non‐transgenic mice. In contrast, no differences in VIP mRNA levels in the cerebral cortex were detected between transgenic and non‐transgenic mice. Treatment with 17(3‐estradiol increased VIP mRNA levels in the anterior pituitary, but not in the cerebral cortex. In concert with the changes in VIP peptide and mRNA, the density of immunoreactive VIP pituitary cells was decreased approximately 50% in hGHRH transgenic mice. In conclusion, unlike galanin gene expression, VIP peptide and mRNA levels are significantly decreased in the anterior pituitary gland of hGHRH transgenic mice. Moreover, these changes appear to be tissue‐specific and are likely due, in part, to the decrease in the density of VIP‐containing pituitary cells in the hyperplastic pituitary. Although the pituitary cell type(s) synthesizing VIP remains unclear, these data suggest that VIP in the anterior pituitary is not stimulating pituitary tumor development in hGHRH transgenic mice.
In vivo Microdialysis of the Hypothalamus: a Suitable Method to Study the Function of Hypophysiotropic Neurons in the Rat
Authors: Cattaneo Lorena , Müller Eugenio E. , Cocchi Daniela
Published: October 2006

Brain microdialysis is a method commonly exploited by neuropharmacologists to study the mechanism of action and preclinical features of centrally acting drugs. It allows measurement of chemical messengers released into the extracellular space, providing a first approximation of neuronal function in selected areas.

In this study we have applied the microdialysis of the hypothalamus to evaluate the release of somatostatin from neurosecretory neurons which are involved in growth hormone regulation and validated this method with different challenges.
Median Preoptic Neurones Projecting to the Supraoptic Nucleus are Sensitive to Haemodynamic Changes as well as to Rise in Plasma Osmolality in Rats
Authors: Aradachi Hiroshi , Honda Kazumasa , Negoro Hideo , Kubota Toshihiko
Published: October 2006

Extracellular single unit activity was recorded from 73 neurones in the median preoptic nucleus (MnPO), identified by antidromic activation as projecting to the supraoptic nucleus (SON) area in urethane‐anaesthetized male rats. Thirteen of 73 identified MnPO neurones were silent, and 44 of 60 spontaneously active MnPO neurones were tested for their responses to electrical stimulation of the nucleus tractus solitarius (NTS). The cells were divided into 4 groups according to their responses; those which were excited orthodromically (OD+; n = 15), those which were unresponsive (UN; n = 21), those which were inhibited orthodromically (OD−; n=4), those which showed initial inhibition followed by excitation (OD+ n = 4). Some of these neurones were further tested for their responses to haemorrhage and/or increase in blood pressure produced by intravenous administration of the oe‐agonist, phenylephrine, and/or to hyperosmotic stimulation produced by intraperitoneal injection of 1.5 M NaCl. Six out of 10 OD+ cells were excited by haemorrhage, 6 out of 11 OD+ cells were inhibited by phenylephrine, and 5 out of 9 OD+ cells were excited by hypertonic saline. On the other hand the UN cells tended to be unresponsive to each type of stimulus. Three out of 7 OD+ cells were excited by both haemorrhage and hypertonic saline, and 3 out of 8 OD+ cells were inhibited by phenylephrine and excited by hypertonic saline. The results may suggest that MnPO neurones which receive afferent input from the NTS may be sensitive not only to haemodynamic change but also to change in plasma osmotic pressure and that such population of MnPO neurones may integrate a part of the haemodynamic and osmotic information and contribute to the control of neurohypophysial hormone release.
Ovarian Steroid Regulation of Estrogen and Progesterone Receptor Messenger Ribonucleic Acid in the Anteroventral Periventricular Nucleus of the Rat
Authors: Simerly R. B. , Carr A. M. , Zee M. C. , Lorang D.
Published: October 2006

The anteroventral periventricular nucleus of the preoptic region (AVPV) represents a key site for hormonal feedback on gonadotropin secretion. It plays a critical role in the neural control of luteinizing hormone secretion and contains high densities of neurons that express receptors for estrogen and progesterone. In this study in situ hybridization was used to examine the expression of mRNAs encoding the estrogen (ER) and progesterone (PR) receptors in the AVPV during the estrous cycle. ER gene expression fluctuated during the cycle with the lowest levels of ER mRNA observed in animals killed on the afternoon of proestrus, and the highest levels present in animals killed during metestrus. This apparent inverse relationship between circulating levels of estradiol (E2) and ER mRNA levels in AVPV neurons was supported by the observation that treatment of ovariectomized rats with E2 suppressed expression of ER mRNA in the AVPV. The influence of progesterone (P4) on ER expression was less pronounced, but a significant increase in ER mRNA in the AVPV was detected 3 h after treatment with P4. In contrast, PR mRNA levels were highest in the AVPV during diestrus and lowest on the morning of proestrus suggesting that PR expression in the AVPV is regulated in a complex manner that may reflect the combined regulatory effects of E2 and P4. E2 treatment caused a dramatic induction of PR mRNA in the AVPV, but P4 did not affect PR mRNA expression acutely, although PR mRNA appears to be attenuated in the AVPV 27 h after P4 treatment. These findings suggest that ovarian steroid hormones regulate ER and PR gene expression in the AVPV during the estrous cycle, which may represent molecular events that contribute to cyclic changes in the responsiveness of AVPV neurons to steroid hormones.
Expression of Somatostatin Receptor (SSTR) Subtypes in Pituitary Adenomas: Quantitative Analysis of SSTR2 mRNA by Reverse Transcription‐Polymerase Chain Reaction
Authors: Murabe Hiroyuki , Shimatsu Akira , Ihara Chihiro , Mizuta Haruo , Nakamura Yoshio , Nagata Izumi , Kikuchi Haruhiko , Nakao Kazuwa
Published: October 2006

The expression of somatostatin receptor (SSTR) subtypes and relative abundance of SSTR2 mRNA were examined in 18 pituitary adenomas using the reverse transcription‐polymerase chain reaction (RT‐PCR) method. SSTR1 and SSTR2 were expressed in all pituitary adenomas examined. Six of 9 somatotroph adenomas, 1 of 4 lactotroph adenomas and 1 of 2 thyrotroph adenomas also expressed SSTR5. SSTR3 and SSTR4 mRNAs were detected in 1 and 2 cases of somatotroph adenoma, respectively. SSTR2 mRNA expression was quantified by comparison with the PCR cycle‐dependent amplification of β‐actin or cyclophilin. The relative abundance of SSTR2 mRNA varied greatly among adenomas with more than a 1000‐fold difference. SSTR2 mRNAs in lactotroph adenomas were less abundant (P<0.01) than those in somatotroph adenomas. No significant correlation was found between the relative abundance of SSTR2 mRNA levels and GH sensitivity to octreotide administration. However, one of the thyrotroph adenomas exhibited marked shrinkage in tumor size after octreotide therapy, in which SSTR2 mRNA was the most abundant among the adenomas examined. GH sensitivity to octreotide was not significantly different between SSTR5 mRNA positive and negative adenomas. In conclusion, SSTR2 mRNA levels varied greatly among pituitary adenomas but were not correlated with GH sensitivity to octreotide. Further investigations of functional SSTR subtype proteins and of postreceptor signal transductions are required to clarify the molecular mechanisms of octreotide action.
Acute Immobilization Stress and Intraventricular Injection of CRF Suppress Naloxone‐Induced LH Release in Ovariectomized Estrogen‐Primed Rats
Authors: Akema Tatsuo , Chiba Atsuhiko , Shinozaki Reiji , Oshida Morihiro , Kimura Fukuko , Toyoda Jun‐ichi
Published: October 2006

The present study was undertaken to evaluate the role and possible interaction of the endogenous opioid peptide (EOP) and corticotropin‐releasing factor (CRF) in the acute stress‐induced suppression of gonadotropin secretion in ovariectomized estrogen‐primed rats. An intravenous (i.v.) injection of naloxone (10 or 20 mg/kg), an EOP antagonist, significantly elevated serum luteinizing hormone (LH) levels within 10 min in non‐stressed animals. The naloxone‐induced LH release was completely eliminated when tested 30 min after the onset of acute immobilization. In a subsequent study, it was found that suppression of the naloxone‐induced LH release occurred as early as 5 min after the stress onset, and was still evident 60 min after the end of a 30‐min period of immobilization. The effect of naloxone was restored 3 h after liberation of the animal from the 30‐min immobilization. An intraventricular (i.c.v.) injection of CRF (1 or 5 μg) also significantly suppressed, in a dose‐related manner, the effect of a subsequent i.v. injection of naloxone. However, an i.c.v. injection of α‐helical CRF(9‐41) (25 or 50 μg), a CRF antagonist, prior to immobilization, could not interfere with the suppressive effect of stress on naloxone‐induced LH release. These results suggest that both acute immobilization stress and CRF can inhibit the LH secretory activity without mediation by EOP neurons. However, the stress‐related suppression may involve non‐CRF mechanism(s).
Melatonin Receptors are Present in Non‐Optic Regions of the Brain of a Deep‐Sea Fish Living in the Absence of Solar Light
Authors: Smith A. , Trudeau V. L. , Williams L. M. , Martinoli M‐G. , Priede I. G.
Published: October 2006

Pineal melatonin hormonally transduces photoperiod to influence daily and seasonal cycles in most vertebrates (1, 2). Evidence of melatonin receptors throughout the brain of several fish species (3–5), particularly in retinorecipient structures, also indicates a role in visual processing. Despite the absence of solar light many deep‐sea organisms show seasonality (6–8). The presence of central melatonin receptors was investigated by quantitative in vitro autoradiography in the deep‐sea fish Coryphaenoides (Nematonurus) armatus. Specific, time‐dependent, saturable, high affinity and guanine nucleotide sensitive, 2‐[125I]iodomelatonin binding was found over the mid‐brain tegmentum and hindbrain. Competing ligand potency was iodomelatonin > melatonin 5‐HT. Although C.(N.) armatus has well developed eyes no 2‐[125I]iodomelatonin binding occurred in optic tectum, cerebellum or hypothalamus. Thus melatonin involvement in processing of visual information and control of seasonal physiology via hypothalamic areas appears to be absent in this species. The presence of central G‐protein coupled receptors indicates a function for melatonin unrelated to solar light.
Molecular Heterogeneity and Glycosylation Modulation of Rat Pituitary Prolactin Isoforms Synthesized and Secreted in vitro in Postnatal Ontogeny, Gestation, Lactation and Weaning
Authors: Bollengier F. , Mahler A. , Matton A. , Vanhaelst L.
Published: October 2006

The modulation of both the molecular size heterogeneity and the relative distribution of rat prolactin variants, synthesized and secreted in vitro by rat pituitary cells in the course of postnatal ontogeny and in gestation, lactation and weaning was investigated by SDS‐PAGE, immunoblotting, radioimmunological techniques and 0‐sialoendopeptidase digestion. The outcome of the experiments is as follows: 1) from day 1 of postnatal life 20‐, 23‐, 26‐, 40–44 kDa and oligomeric rat prolactin isoforms were stored and secreted; 2) perinatal life is characterized by a high degree of variability of prolactin size isoforms and their respective repartition in storage and release; in addition to the major variants, transient ones of Mr 25‐, 28‐, 33‐ and 36 kDa were secreted and/or stored; 3) O‐sialoglycoprotease digestion of pituitary cell lysate gave good evidence for 25 kDa prolactin being a glycoform; 4) at 1 month of age 16 kDa rat prolactin appeared and persisted over the whole postnatal span (1 day → 1 year) but only in stored form; 5) the physiology of gestation was essentially characterized by the Mr‐modulation of the glycoform (26 kDa → 26.3 kDa) and the virtual absence of stored 26 kDa rat prolactin at week 1 of pregnancy; 6) in lactation and weaning uncommon multiple banding was observed in secreted oligomeric prolactin; 7) in pregnancy, lactation and weaning the differential distribution of released and stored prolactin isoforms displayed a considerable intra‐ and intervariability; 8) in the vast array of size isoforms observed in all our experiments monomeric 23 kDa prolactin was always the dominating variant. In conclusion, the molecular size heterogeneity and the differential distribution of secreted and stored rat pituitary prolactin is considerably influenced by age and physiological stimuli. The nature of polymeric prolactin and of the transient variants is presently unclear, and the exact physiological role of molecular heterogeneity modulation is unknown, both in humans and rat, but the patterns of change we observed in definite stages of life, suggest that this phenomenon is important in the maturation of the hypothalamus‐pituitary axis and in the metabolic and hormonal changes accompanying gestation.
Different Effects of Somatostatin on in vitro Growth Hormone Release in Two Porcine Breeds with Different Growth Rates1
Authors: Torronteras Rafael , Gracia‐Navarro F. , Elsaesser Folkmar
Published: October 2006

A perifusion system of anterior pituitary (AP) tissue was used to investigate the temporal interaction of growth hormone‐releasing factor (GRF) and somatostatin (SRIF) in the control of GH secretion in two pig breeds, Göttingen Miniature Pig (GMP), a small obese breed, and German Landrace (GLR), a conventional lean breed. AP tissue pieces derived from sexually mature ovariectomized animals were perifused (6 replicates per treatment) and fractions were collected at 10 min intervals. Basal GH release (ng‐mP‐1 mg‐1 AP) in GLR was twice that of GMP (P < 0.001). Exposure to 10 min pulses of 1 nM GRF repeated 3 times at 2 h intervals resulted in rapid stimulatory GH responses (area under the curve) which became attenuated (P < 0.05) over time in GMP but not in GLR. Surprisingly, during and following the exposure of AP tissue from GMP to 10‐, 20‐, or 40‐min pulses of 10 nM SRIF alone, GH release was markedly stimulated (P < 0.05), while AP tissue from GLR only showed a weak rebound GH release after SRIF pulses. With AP tissue from GLR low concentrations (0.1 nM SRIF) amplified GRF‐induced GH release, whereas 1 nM or 10 nM SRIF inhibited GRF‐induced GH release. However, concomitant exposure of AP tissue from GMP to 0.1, 1 or 10 nM SRIF during a GRF pulse markedly enhanced the GH response (P < 0.05), compared to 1 nM GRF alone, except for 1 nM SRIF which inhibited the GH response to the first GRF pulse. Thus the presence of SRIF, and not only its withdrawal, is an important factor in setting the timing and duration of GH pulses in both breeds. In GLR the concentration of SRIF is more important than the duration and/or type of SRIF pulse. In contrast, in GMP type and/or duration of SRIF pulses seem to be crucial to optimize pulsatile GH release and even determine peak height of GH pulses caused by GRF. These findings indicate clear breed differences in the role of SRIF and in the control of GH release by the interplay of GRF and SRIF. The ‘paradoxical’ effect of SRIF suggests that the role of SRIF is much more complex than that of a mere inhibitor and whose real role could be a modulator either of GH pulse and/or GRF action on GH release.
Changing Effect of i.c.v. IL‐1β on Vasopressin Release in Anaesthetized, Female Rats at Different Stages of Lactation: Role of Prostaglandins and Noradrenaline
Authors: Wilson Brian C. , Fulop Kathleen , Summerlee Alastair J. S.
Published: October 2006

lnterleukin‐1β stimulates oxytocin and vasopressin release in conscious, male rats and causes a rise in blood pressure. These experiments were done to: A) examine the effect of i.c.v. interieukin‐1 β (1 ng/μl) on circulating levels of vasopressin in female rats at different stages of lactation and B) determine if α‐adrenergic mechanisms and/or prostaglandins were involved as mediators. Urethane‐anaesthetized non‐lactating rats and rats at Day 7, 10, 20 and 26 of lactation were set up for arterial blood sampling and i.c.v. injections. One mL blood samples were obtained in one min periods before, and at 1, 2.5, 5, 10, 30, 60 and 120 min after the following treatments: i.c.v. treatment with either interleukin‐1β (1 ng in 1 μl PBS‐BSA) or PBS‐BSA (1 μl) as a vehicle control; or i.c.v. treatment with interleukin‐1β following pretreatment with either phentolamine (1.7 ng/μl i.c.v.) or indomethacin (1 ng/μl i.c.v.). As blood was sampled, isotonic saline was infused (1 mL per min) and blood pressure was monitored to minimize any hypovolemic effects due to sampling. Extracted plasma was assayed using a specific vasopressin radioimmunoassay, lnterleukin‐1 β i.c.v. stimulated the release of vasopressin above that elicited by PBS‐BSA alone in non‐lactating rats resulting in an approximate 1.2 to 2‐fold increase in plasma hormone levels. Throughout the first half of lactation, vasopressin responsiveness to i.c.v. interleukin‐1β treatment was markedly attenuated. In latter stages of lactation, the response recovered and resembled that of non‐lactators around the time of weaning. Prostaglandins consistently mediate a stimulatory action of interleukin‐1β on vasopressin release whereas α‐adrenergic mechanisms mediate a depression of interleukin‐1β‐induced vasopressin release during the early to middle stages of lactation. It is possible that the depression in interleukin‐1β‐stimulation of vasopressin release in early to mid‐lactation is conducive for nursing to occur and that the increase in vasopressin responsiveness towards the latter stages of lactation represents a component of the weaning process.
A Subset of Estrogen Receptor‐Containing Neurons Project to the Median Eminence in the Ewe
Authors: Jansen Heiko T. , Hileman Stanley M. , Lubbers Laura S. , Jackson Gary L. , Lehman Michael N.
Published: October 2006

The neural pathways responsible for conveying the steroid feedback signals that ultimately affect reproductive neuroendocrine function remain largely undefined. One possibility involves a direct projection from estrogen receptor (ER)‐containing neurons to the median eminence (ME), a site of neuroendocrine peptide release. To examine this possibility, 8 ewes received stereotaxic injections of the retrograde neuronal tract‐tracing compound cholera toxin‐β subunit (CTβ) into the ME. Neurons sending projections to the ME and containing ER were identified using a dual‐label immunoperoxidase method. Double‐labeled cells were found in distinct regions: (1) the ER‐rich arcuate nucleus (ARC) that contained the greatest number of double‐labeled cells, and (2) the organum vasculosum of the lamina terminalis (OVLT) which contained a very consistent, but low, number of double‐labeled cells. While a fairly large number of retrogradely‐labeled ARC neurons containing ER were identified, the majority of ER‐containing ARC neurons were unlabeled and thus send projections elsewhere. Other regions containing high concentrations of ER‐positive cells such as the medial preoptic area (MPOA), anterior hypothalamic area, and ventrolateral portion of the ventromedial hypothalamic nucleus, were devoid of double‐labeled cells. Similarly, regions rich in neuroendocrine neurons such as the periventricular hypothalamus and paraventricular and supraoptic hypothalamic nuclei contained no double‐labeled cells. These results suggest that modulation of neuroendocrine secretory activity may occur directly at the level of the ME by ER‐containing neurons located within restricted regions of the hypothalamus and forebrain. However, the relatively low proportion of ER‐containing neurons projecting to the ME suggests that the influence of estradiol upon neuroendocrine function also may include target sites other than the ME.