bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vivo Modulation of Post‐Spike Excitability in Vasopressin Cells by κ‐Opioid Receptor Activation
Authors: Brown C. H. , Leng G. 
Published: March 2003

AbstractAn endogenous κ‐opioid agonist reduces the duration of phasic bursts in vasopressin cells. Non‐synaptic post‐spike depolarizing after‐potentials underlie activity during bursts by increasing post‐spike excitability and κ‐receptor activation reduces depolarizing after‐potential amplitude in vitro. To investigate the effects of κ‐opioids on post‐spike excitability in vivo, we analysed extracellular recordings of the spontaneous activity of identified supraoptic nucleus vasopressin cells in urethane‐anaesthetized rats infused with Ringer's solution (n = 17) or the κ‐agonist, U50,488H (2.5 µg/h at 0.5 µl/h; n = 23), into the supraoptic nucleus over 5 days. We plotted the mean hazard function for the interspike interval distributions as a measure of the post‐spike excitability of these cells. Following each spike, the probability of another spike firing in vasopressin cells recorded from U50,488H infused nuclei was markedly reduced compared to Ringer's treated vasopressin cells. To determine whether U50,488H could reduce post‐spike excitability in cells that displayed spontaneous phasic activity, we infused U50,488H (50 µg/h at 1 µl/h, i.c.v.), for 1–12 h while recording vasopressin cell activity. Nine of 10 vasopressin cells were silenced by i.c.v. U50,488H 15 ± 5 min into the infusion. Six cells exhibited spontaneous phasic activity before U50,488H infusion and recordings from three of these phasic cells were maintained until activity recovered; during U50,488H infusion, the activity of these three cells was irregular. Generation of the mean hazard function before and during U50,488H infusion revealed a reduction in post‐spike excitability during U50,488H infusion. Thus, κ‐receptor activation reduces post‐spike excitability in vivo; this may reflect inhibition of depolarizing after‐potentials and may thus underlie the reduction in burst duration of vasopressin cells caused by an endogenous κ‐agonist in vivo.
Adrenomedullin Acts in the Rat Paraventricular Nucleus to Decrease Blood Pressure
Authors: Smith P. M. , Ferguson A. V. 
Published: March 2003

AbstractAdrenomedullin is a recently discovered peptide involved in the control of fluid and electrolyte homeostasis and cardiovascular function through peripheral and central nervous system actions. The present study was undertaken to examine the cardiovascular effects of adrenomedullin microinjection directly into the paraventricular nucleus (PVN). Microinjection of adrenomedullin into the PVN of urethane anaesthetized male Sprague‐Dawley rats resulted in site‐specific, repeatable decreases in blood pressure. These hypotensive effects were found to be dose related, and were not mediated by activation of calcitonin gene‐related peptide receptors. These data suggest that adrenomedullin influences cardiovascular regulation through receptor mediated actions at the PVN of the hypothalamus.
The Effect of Acute and Chronic Restraint on the Central Expression of Prepro‐Neuropeptide Y mRNA in Normotensive and Hypertensive Rats
Authors: Sweerts B. W. , Jarrott B. , Lawrence A. J. 
Published: March 2003

AbstractNeuropeptide Y (NPY), one of the most abundant neuropeptides found in the central nervous system (CNS), has been implicated in the regulation of many autonomic functions, including cardiovascular control and the central stress response. The present study represents a detailed investigation of the effects of acute and chronic restraint stress on the expression of the mRNA encoding the NPY precursor, prepro‐NPY, in the CNS of normotensive Wistar‐Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) using in situ hybridization histochemistry. Basal (unstressed) levels of prepro‐NPY mRNA expression were found to be significantly increased in the hypothalamic arcuate nucleus of SHR compared to WKY rats, with similar levels of prepro‐NPY mRNA expression found in the remaining central nuclei. Following exposure to both acute and chronic restraint, significant changes in prepro‐NPY mRNA expression were found in a variety of central regions in both strains, including the arcuate nucleus and hippocampus (both strains), medial amygdala and cortex (WKY only), and dentate gyrus, nucleus of the solitary tract and ventrolateral medulla (SHR only). A comparison of the temporal response to restraint revealed that significant differences between strains existed in regions such as the arcuate nucleus, hippocampus and dentate gyrus, providing further evidence that hypertensive rats apparently have an impaired neural stress response. The present study demonstrates that exposure to restraint results in significant changes in prepro‐NPY mRNA expression in specific nuclei of both WKY and SHR that are components of not only the central circuitry regulating the stress response, but also the neural network modulating autonomic function.
Butyl Benzyl Phthalate, an Endocrine Disrupter, Inhibits Pulsatile Luteinizing Hormone Secretion Under an Insulin‐Induced Hypoglycaemic State in Ovariectomized Rats
Authors: Kawaguchi M. , Funabashi T. , Aiba S. , Kimura F. 
Published: March 2003

AbstractButyl benzyl phthalate (BBP) and bisphenol A (BPA), termed endocrine disrupters, are known to mimic oestrogen in their actions, and therefore there is concern about their effect on reproductive functions. Since it is reported that the inhibitory action of oestrogen on the pulsatile secretion of luteinizing hormone (LH) is enhanced under insulin‐induced hypoglycaemia, whether this also applies to BBP and BPA was examined in the present study. In adult ovariectomized (OVX) rats, the pulsatile LH secretion 24 h after subcutaneous injection of 10 mg BBP (BBP‐treated), 10 mg BPA (BPA‐treated) or 100 ng 17β‐oestradiol (E2‐treated), all of which were dissolved in sesame oil, was not changed significantly compared to that after the injection of sesame oil only. Furthermore, in oil‐treated OVX rats, the pulsatile LH secretion immediately after intravenous injection of insulin (1.0 U) was not changed compared to that after saline injection. In BBP‐treated OVX rats, the injection of insulin (1.0 U) significantly decreased the number of LH pulses as in E2‐treated OVX rats. The injection of insulin did not significantly affect the amplitude of LH pulses in BBP‐, BPA‐ and E2‐treated OVX rats. The results indicate that the oestrogenic action of BBP is significantly enhanced by insulin‐induced hypoglycaemia and thus the pulsatile LH secretion is inhibited. We suggest that weak oestrogenic endocrine disrupters may become harmful to reproductive functions even in adult female rats, if acting under a low energy state.
Overexpression of the V3 Vasopressin Receptor in Transgenic Mice Corticotropes Leads to Increased Basal Corticosterone
Authors: René P. , Grino M. , Viollet C. , Videau C. , Jullian E. , Bucchini D. , Epelbaum J. , Bertagna X. , De Keyzer Y. 
Published: March 2003

AbstractThe vasopressin V3 receptor (V3) is specifically expressed in pituitary corticotropes and mediates the stimulatory effect of vasopressin on adrenocorticotropic hormone (ACTH) release. The V3 gene is overexpressed in corticotrope pituitary tumours compared to normal pituitaries. We hypothesized that V3 overexpression might induce changes in corticotrope function and alter the regulation of the hypothalamic‐pituitary‐adrenal axis. Thus, we generated transgenic mice (POMV3) expressing the human V3 receptor in the pituitary under the control of rat pro‐opiomelanocortin (POMC) promoter sequences. The transgene was efficiently transcribed and vasopressin binding was increased in both corticotropes and melanotropes. In‐vitro ACTH release and inositol phosphate formation were unchanged in POMV3 pituitaries, but the responses to vasopressin were significatively increased. In vivo, basal circulating concentrations of ACTH in POMV3 mice were similar to those of controls but corticosterone concentrations were moderately increased. In addition, the levels of POMC mRNA in the transgenic pituitaries were comparable to those of control mice. Finally, POMV3 mice responded with a similar maximal increase of ACTH and corticosterone to a 20‐min acute restraint stress. Together, these results show that hypophyseal V3 overexpression led to increased basal concentrations of corticosterone and suggest that the negative glucocorticoid feedback may be altered at the pituitary level.
Functional Cooperation Between Neurosteroids and D2 Dopamine Antagonists on KCl‐Evoked [3H]Noradrenaline Release: Modulation By Calcium Channel Blockers
Authors: Monnet F. P. 
Published: March 2003

AbstractIt has recently been proposed that neurosteroids, such as dehydroepiandrosterone sulphate and pregnenolone sulphate, interfere with the dopamine system in the central nervous system. According to our previous report showing that the butyrophenone, spiperone, slightly enhances the evoked release of [3H]‐noradrenaline ([3H]NA) in the presence of these sulphated steroids, the present study was carried out to document the putative interplay between steroids and spiperone, which is known to be a prototypic D2 dopamine antagonist and also a 5‐HT2 serotonin antagonist. For this purpose, the paradigm of KCl‐evoked [3H]NA release from preloaded rat hippocampal slices was used to investigate the interactions between neurosteroids, spiperone and the voltage‐sensitive calcium channels (VSCCs). The selective 5‐HT2 serotonin antagonist ritanserine was ineffective, whereas sulpiride, a selective D2 dopamine antagonist mimicked the action of spiperone, thus suggesting that the blockade of D2 dopamine receptors accounted for the modulatory effect of spiperone on neurosteroid‐induced modulation of evoked [3H]NA release. In addition, this facilitation of KCl‐evoked [3H]NA release by the combination of a steroid and a D2 dopamine antagonist was partially inhibited by the L‐ and N‐type VSCC blockers nifedipine and ω‐conotoxin GVIA, respectively. The present results provide in‐vitro functional evidence for the putative role of VSCCs in the interplay between steroids and D2 dopamine receptors.
Effect of Direct Injection of Melanin‐Concentrating Hormone into the Paraventricular Nucleus: Further Evidence for a Stimulatory Role in the Adrenal Axis via SLC‐1
Authors: Kennedy A. R. , Todd J. F. , Dhillo W. S. , Seal L. J. , Ghatei M. A. , O'Toole C. P. , Jones M. , Witty D. , Winborne K. , Riley G. , Hervieu G. , Wilson S. , Bloom S. R. 
Published: March 2003

AbstractMelanin‐concentrating hormone (MCH) is implicated in the control of a number of hormonal axes including the hypothalamic‐pituitary adrenal (HPA) axis. Previous studies have shown that there is evidence for both a stimulatory and an inhibitory action on the HPA axis; therefore, we attempted to further characterize the effects of MCH on this axis. Intracerebroventricular injection of MCH increased circulating adrenocorticotropic hormone (ACTH) at 10 min post injection. Injection of MCH directly into the paraventricular nucleus (PVN) was found to increase both circulating ACTH and corticosterone 10 min after injection. Additionally, MCH was found to increase corticotropin‐releasing factor (CRF) release from hypothalamic explants, and this effect was abolished by the specific SLC‐1 antagonist SB‐568849. Neuropeptide EI, a peptide from the same precursor as MCH was also found to increase CRF release from explants. These results suggest that MCH has a stimulatory role in the HPA axis via SLC‐1, and that MCH exerts its effects predominantly through the PVN CRF neuronal populations
Finishing and polishing of the ceromer material Targis. Lab‐side and chair‐side methods
Authors: Behr M. , Rosentritt M. , Leibrock A. , Schneider‐Feyrer S. , Handel G. 
Published: March 2003

The aim of the study was to check four lab‐side and four chair‐side methods for finishing and polishing the ceromer material Targis®. Eighty bar‐shaped specimens (20 mm × 10 mm × 2 mm) of Vectris were produced; 72 were covered with a 2 mm (thickness) layer of the Ceromer Targis® and eight samples with the composite Tetric®. All specimens were ground plane parallel with 320 Silicium carbide grit sandpaper in order to start with the same level of roughness. Then the specimens were finished and polished using the following methods: (1) Artglass® toolkit, (2) pumice‐stone and brushes/linen brush and polishing paste P3, (3) Robinson® brush/Ivoclar Universal® paste and wool brush, (4) Silicone wheel and rag wheel, (5) Shofu Rainbow® set, (6) Sof‐Lex® discs, (7) Vivadent Politip® set and (8) Nupro‐pastes® and brushes. The surface roughness was determined with a profilometer. The arithmetical roughness value Ra was calculated. From each group one specimen was randomly chosen and sputtered with gold in order to observe the surface with a scanning electron microscope to evaluate its smoothness. The methods were ranked as followed: 2, 3 and 5 with the lowest roughness, then 8, 6, 7, 4, 1. The best ranked chair‐side method (5) and the best ranked lab‐side methods (2, 3) did not differ significantly between the Ra values. No difference was observed between the composite Tetric® and the ceromer Targis® when these materials were polished using the same method.Conclusion: the lab‐side‐methods 2 and 3 and the chair‐side‐method 5 can be recommended for finishing and polishing the new ceromer material Targis®.
Differences in chewing strategies used by edentate people
Authors: HEATH M. R. , MORRIS J. R. , FERMAN A. M. 
Published: March 2003

Aim:  To examine, in detail, the different masticatory measures that contribute to individual chewing strategies of edentate people.Measures:  Variables relating to displacement and force were derived using a new three dimensional implant force transducer, a mucosal pressure transducer and measurements of mandibular movements.Materials:  Five edentate subjects with conventional upper dentures and lower dentures stabilized on two dental implants. The subjects chewed unilaterally on their preferred chewing side. Seven foods were chewed – almond, fruit pastille, chewing gum and four different meats.Analysis:  The data were analysed by separating each sequence into cycles and ‘phases’ of cycles for which variables were derived.Results:  As expected, the results showed greater differences between subjects than between foods. From the five subjects, four basic strategies were identified in response to the different foods: one subject primarily modulated force, one subject modulated the number of cycles, two subjects modulated force and the number of cycles and one subject showed little modulation at all. As part of these strategies many striking differences between subjects were observed, e.g. one subject showed little modulation of her ‘default’ chewing pattern for different foods, yet one subject modulated the number of force and manipulation cycles, the force strategy (forces increasing through sequences) and swallow thresholds.Conclusion:  People appear to develop different strategies to compensate for chewing difficulty by modulating speed, the number of cycles and/or penetration forces.
Acute inflammatory response to dentine‐bonding
Authors: PETERS H. , REZWANI T. , GAENGLER P. , HERTER P. , KINNE R. K. H. , KINNE E. 
Published: March 2003

The phlogogenic potential of dentine‐bonding‐agents is still disputed. It was the aim of this study to demonstrate acute pulpal inflammation in teeth that were treated with a glutaraldehyde and HEMA containing primer.Twenty‐two Wistar rats underwent microsurgical preparation of a lower incisor in accordance with the vital microscopy usage oriented biocompatibility test. Sixteen animals were divided into two test groups. Their teeth were treated with the primer for 20 s (n=8) and 10 min (n=8). Six animals comprised the control group (n=6).During a 120‐min follow up the pulpal blood circulation was investigated for haemodynamic changes. The animals were killed and pulpal specimens were stained immunohistochemically.CD43 positive cells were labelled by incubation with W3/13 monoclonal antibodies. CD43 is a highly expressed surface antigen on polymorph neutrophil granulocytes (PMN). By this means, the amount and distribution of infiltrating PMN in the affected pulp could be demonstrated.Vital microscopic observation of the pulpal blood circulation showed irreversible stasis and thrombosis after primer application. The intensity of the haemodynamic changes was dependent on application duration.The semiquantitative determined influx of PMN was highest in pulps of teeth that had been primed for 10 min. Control teeth never showed irreversible circulatory changes nor highly elevated PMN influx. From these results it can be concluded that the tested primer has a phlogogenic potential in pulp‐close cavities. The combined method of in vivo blood circulation observation and immunofluorescence microscopic demonstration of target cells serves as a good indicator for acute inflammatory responses.
The clinical assessment of TMJ sounds by means of auscultation, palpation or both
Authors: HUDDLESTON‐SLATER J. J. R. , VAN SELMS M. K. A. , LOBBEZOO F. , NAEIJE M. 
Published: March 2003

Anterior disc displacements are an important diagnostic subgroup (Group II) of TM disorders according to the Research Diagnostic Criteria (RDC; Dworkin & LeResche, 1992). Although the RDC yields clear‐cut criteria for the diagnosis of a disc displacement, the interobserver reliability for the clinical recognition of joint sounds is highly variable. This high variance may be caused by the fact that the clinical assessment of joint sounds is difficult. In many previous studies, auscultation with a stethoscope was used. This technique is often claimed to be the most reliable one. However, it is unclear whether in these studies, auscultation was performed without simultaneous palpation of the contralateral joint. Therefore, the aim of the present study was to test the interobserver reliability of the clinical assessment of TMJ sounds by means of auscultation, palpation or both. A total of 220 undergraduate students (100 men; 120 women; mean age 21·9 ± 3·6 years) was examined independently by two calibrated dentists for the presence, probable presence or absence of sounds caused by anterior disc displacement, hypermobility, or another cause. The 79 students underwent auscultation only (i.e. without contralateral manual palpation); 87 students underwent bilateral palpation; the remainder (54 students) was subjected to both auscultation and palpation. The results show that the combination technique yields the highest reliability (Cohen's κ=0·53). For other techniques, κ‐values of 0·46 (auscultation) and 0·48 (palpation) were found. It was concluded that the combination of auscultation and palpation yields the highest interobserver reliability for the recognition of TMJ sounds, although the differences with other techniques were small. (Supported by the IOT)
Pharmacokinetics of carprofen enantiomers in equine plasma and synovial fluid – a comparison with ketoprofen
Authors: Armstrong S. , Tricklebank P. , Lake A. , Frean S. , Lees P. 
Published: March 2003

Carprofen is a Non Steroidal Anti‐Inflammatory Drug (NSAID) which is widely used for the treatment of musculoskeletal disorders in horses. The commercial preparation is a racemic mixture of two enantiomers (R and S carprofen). We used HPLC to measure plasma and synovial fluid R and S carprofen concentrations following a single intravenous (i.v.) dose, and computer modelling to determine the pharmacokinetic parameters of the enantiomers in these two body fluids. A comparison was made with results from an identical experiment using ketoprofen. The plasma elimination half lives of R and S carprofen were 20 and 16 times longer than those of R and S ketoprofen, and clearance was considerably slower for carprofen than ketoprofen. Plasma R carprofen concentrations were higher than S carprofen concentrations throughout the 48‐h period. Ketoprofen was no longer detectable in synovial fluid after 5 h (S enantiomer) or 12 h (R enantiomer), whereas synovial fluid carprofen concentrations did not peak until 12 h and were still detectable at 48 h. Synovial fluid concentrations of both carprofen enantiomers were significantly lower than plasma concentrations, probably due to high plasma protein binding which could limit transfer through the synovial membrane. Our results indicate significant differences between carprofen and ketoprofen and between the two carprofen enantiomers.
A multilocation clinical trial in lactating dairy cows affected with clinical mastitis to compare the efficacy of treatment with intramammary infusions of a lincomycin/neomycin combination with an ampicillin/cloxacillin combination
Authors: Deluyker  , Chester  , Van Oye  
Published: March 2003

A study was conducted to compare the efficacy in lactating dairy cows of intramammary infusions in quarters affected with clinical mastitis between a formulation containing 330 mg lincomycin and 100 mg neomycin in a 10‐mL aqueous solution (LINCOCIN® FORTE S, Pharmacia & Upjohn) and a formulation containing 75 mg ampicillin and 200 mg cloxacillin in an oil suspension (AMPICLOX™, Pfizer Animal Health).This study was designed as a multicentre clinical trial involving investigators in France, Germany and Belgium and carried out according to the European Commission guidelines on Good Clinical Practices. Cows in the herds were monitored for clinical mastitis. When evidence of clinical mastitis was detected in a single quarter, a pretherapy milk sample was collected from the affected quarter. After milk sampling, the cow was assigned to one of the two treatment groups at random and treated with an intramammary infusion of one syringe of either LINCOCIN® FORTE S or AMPICLOX™ for three successive milkings in the mastitic quarter. At 4–5, 13–15 and 20–22 days after first infusion, the veterinarian returned to the farm to conduct a clinical examination and collect milk samples from the affected quarter. Milk samples were cultured for the presence of mastitis organisms and somatic cell count (SCC) was measured.Following a 10‐month study period, 256 cases were enrolled in the study. A total of 232 and 189 cases were analysed for clinical cure and for clinical‐plus‐bacteriological cure, respectively. The proportions of cases cured clinically and cured clinically‐plus‐bacteriologically were compared between the two treatment groups. Somatic cell count differences between treatment groups were also tested. The clinical cure rate for LINCOCIN® FORTE S (62.5%) was significantly better than for AMPICLOX™ (51.8%) (P = 0.035). The clinical‐plus‐bacteriological cure rate was also significantly better for LINCOCIN® FORTE S (38.1%) than for AMPICLOX™ (21.7%) (P = 0.005). Among bacteriologically cured cases, the SCC declined in both treatment groups but the SCC was significantly higher for the AMPICLOX™ group than for the LINCOCIN® FORTE S group (P = 0.036).In conclusion, clinical cure rate, clinical‐plus‐bacteriological cure rate, and SCC level were significantly better with LINCOCIN® FORTE S than for AMPICLOX™.