bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of treatment with melatonin on cerebral circulation in old rats
Authors: Dupuis François , Régrigny Olivier , Atkinson Jeffrey , Limiñana Patrick , Delagrange Philippe , Scalbert Elizabeth , Chillon Jean‐Marc 
Published: February 2004

Melatonin deprival in young rats induces alterations in cerebral arteriolar wall similar to those observed during aging: atrophy and a decrease in distensibility. In this study, we examined the effects of melatonin treatment on cerebral arteriolar structure and distensibility and on the lower limit of cerebral blood flow autoregulation (LLCBF) in old rats.
We measured cerebral blood flow (arbitrary unit, laser Doppler, open skull preparation) prior to and during stepwise hypotension (SH) in adult (12/13 months) and old (24/25 months) IcoWI and WAG/Rij male rats. Old rats were untreated or treated for 3 months with melatonin (0.39 (IcoWi) and 0.44 (Wag/Rij) mg kg−1 day−1, drinking water). Stress–strain relationships were determined using cross‐sectional area (CSA, μm2, histometry) and values of arteriolar internal diameter (μm) obtained during a second SH following arteriolar deactivation (EDTA, 67 mmol l−1).
Aging induced (a) atrophy of the arteriolar wall in IcoWI (616±20 vs 500±27 μm2, P<0.05) but not in WAG/Rij rats (328±25 vs 341±20 μm2), (b) a decrease in arteriolar wall distensibility and (c) an increase in the LLCBF in both strains (67±10 mmHg in 12‐month‐old vs 95±6 mmHg in 24‐month‐old IcoWi, P<0.05 and 53±2 mmHg in 13‐month‐old vs 67±6 mmHg in 25‐month‐old WAG/Rij).
Melatonin treatment induced in IcoWI and WAG/Rij rats (a) hypertrophy of the arteriolar wall (643±34 and 435±25 μm2, respectively), (b) an increase in arteriolar wall distensibility and (c) a decrease in the LLCBF (64±6 and 45±4 mmHg, respectively).
Melatonin treatment of old rats induced hypertrophy of the arteriolar wall, prevented the age‐linked decrease in cerebral arteriolar distensibility and decreased the LLCBF.

British Journal of Pharmacology (2004) 141, 399–406. doi:10.1038/sj.bjp.0705629
Na+/H+ exchange inhibition attenuates left ventricular remodeling and preserves systolic function in pressure‐overloaded hearts
Authors: Marano Giuseppe , Vergari Alessandro , Catalano Liviana , Gaudi Simona , Palazzesi Sergio , Musumeci Marco , Stati Tonino , Ferrari Alberto U 
Published: February 2004

Cardiac hypertrophy is a homeostatic response to elevated afterload. Na+/H+ exchanger (NHE) inhibition reduces the hypertrophic response in animal models of left ventricular hypertrophy (LVH) and myocardial infarction. We examined the effect of chronic treatment with cariporide, a selective inhibitor of Na+/H+ exchanger isoform 1 (NHE‐1), on left ventricular (LV) systolic and diastolic function under pressure overload conditions.
Male CD‐1 mice were randomized to receive either a control diet or an identical diet supplemented with 6000 p.p.m. of cariporide. Cardiac pressure overload was induced by thoracic aortic banding. LV dimension and systolic and diastolic function were assessed in sham and banded mice by echocardiography and cardiac catheterization 2 and 5 weeks after surgery. Histological analysis was also performed.
After 2 weeks of pressure overload, the vehicle‐treated banded mice (Veh‐Bd) had enhanced normalized LV weight (about +50%) and normal chamber size and function, whereas cariporide‐treated banded mice (Car‐Bd) showed a preserved contractility and systolic function despite a marked attenuation of LVH. Diastolic function did not differ significantly among groups. After 5 weeks, the Veh‐Bd developed LV chamber enlargement and systolic dysfunction as evidenced by a 16% increase in LV end‐diastolic diameter, a 36% decrease in myocardial contractility, and a 26% reduction in percent fractional shortening. In contrast, Car‐Bd showed an attenuated increase in LV mass, normal chamber size, and a maintained systolic function. A distinct histological feature was that in banded mice, cariporide attenuated the development of cardiomyocyte hypertrophy but not the attendant myocardial fibrosis.
In conclusion, the results of the present study indicate that (i) the hypertrophic response to pressure overload is dependent on NHE‐1 activity, and (ii) at the 5‐week stage, banding‐induced deterioration of LV performance is prevented by NHE‐1 inhibition.

British Journal of Pharmacology (2004) 141, 526–532. doi:10.1038/sj.bjp.0705631
Brain‐derived neurotrophic factor (BDNF) contributes to neuronal dysfunction in a model of allergic airway inflammation
Authors: Braun Armin , Lommatzsch Marek , Neuhaus‐Steinmetz Ulrich , Quarcoo David , Glaab Thomas , McGregor Gerard P , Fischer Axel , Renz Harald 
Published: February 2004

Brain‐derived neurotrophic factor (BDNF) is a candidate molecule for mediating functional neuronal changes in allergic bronchial asthma. Recently, enhanced production of BDNF during allergic airway inflammation caused by infiltrating T‐cells and macrophages as well as by resident airway epithelial cells has been described. It was the aim of this study to investigate the effect of enhanced BDNF levels on lung function and airway inflammation in a mouse model of allergic inflammation.
Ovalbumin‐sensitised BALB/c mice were challenged in two consecutive allergen challenges. Prior to the challenge, the mice were treated with either anti‐BDNF antibodies or isotype‐matched control antibodies. Airway responsiveness to methacholine, capsaicin and electric field stimulation, as well as airway inflammation and chronic airway obstruction 1 week after the last allergen challenge were assessed.
Anti‐BDNF blocked enhanced reactivity in response to capsaicin, but not airway smooth muscle hyper‐reactivity in vivo. Furthermore, persistent airway obstruction, as observed 1 week after the last allergen challenge, was to a large extent prevented by anti‐BDNF treatment. In vitro, BDNF and anti‐BDNF treatment had a profound effect on local neuronal hyper‐reactivity, as shown by electric field stimulation experiments. In contrast, neither BDNF nor anti‐BDNF treatment affected airway inflammation.
Our data indicate that development of allergen‐induced neuronal hyper‐reactivity in mice is partially mediated by BDNF.

British Journal of Pharmacology (2004) 141, 431–440. doi:10.1038/sj.bjp.0705638
Epoxyeicosatrienoic acids mediate adenosine‐induced vasodilation in rat preglomerular microvessels (PGMV) via A2A receptors
Authors: Cheng M K , Doumad A B , Jiang H , Falck J R , McGiff J C , Carroll M A 
Published: February 2004

Activation of rat adenosine 2A receptors (A2A R) dilates preglomerular microvessels (PGMV), an effect mediated by epoxyeicosatrienoic acids (EETs).
Incubation of PGMV with a selective A2A R agonist, 2‐p‐(2‐carboxyethyl) phenethylamino‐5′‐N‐ethylcarboxamidoadenosine (CGS 21680; 100 μM), increased isolated PGMV EET levels to 7.57±1.53 ng mg−1 protein from 1.06±0.22 ng mg−1 protein in controls (P<0.05), without affecting hydroxyeicosatetraenoic acid (HETE) levels (10.8±0.69 vs 11.02±0.74 ng mg−1 protein).
CGS 21680‐stimulated EETs was abolished by preincubation with an A2A R antagonist, 4‐(2‐[7‐amino‐2‐(2‐furyl)[1,2,4]triazolo[2,3‐a][1,3,5]triazin‐5‐ylamino]ethyl)phenol (ZM241385) (100 μM). A selective epoxygenase inhibitor, methylsulfonyl‐propargyloxyphenylhexanamide (MS‐PPOH; 12 μM) prevented CGS 21680‐induced increase in EETs, indicating inhibition of de novo synthesis of EETs.
In pressurized (80 mmHg) renal arcuate arteries (110–130 μm) preconstricted with phenylephrine (20 nM), superfusion with CGS 21680 (0.01–10 μM) increased the internal diameter (i.d.) concentration‐dependently; vasodilation was independent of nitric oxide and cyclooxygenase activity. CGS 21680 (10 μM) increased i.d. by 32±6 μm; vasodilation was prevented by inhibition of EET synthesis with MS‐PPOH.
Addition of 3 nM 5,6‐EET, 8,9‐EET and 11,12‐EET increased i.d. by 53±9, 17±4 and 53±5 μm, respectively, whereas 14,15‐EET was inactive. The responses to 5,6‐EET were, however, significantly inhibited by indomethacin.
We conclude that 11,12‐EET is the likely mediator of A2A R‐induced dilation of rat PGMV. Activation of A2A R coupled to de novo EET stimulation may represent an important mechanism in regulating preglomerular microvascular tone.

British Journal of Pharmacology (2004) 141, 441–448. doi:10.1038/sj.bjp.0705640
Reforming the Expenditure Budget Process: The Canadian Experience
Authors: Savoie Donald J. 
Published: February 2004

During the past twenty years the government of Canada has introduced three distinct approaches to managing its expenditure budget. The approaches were all introduced with considerable fanfare and also with the promise that they would enable the government to finally get a firm handle on its expenditure budget.This paper looks at the three approaches and outlines their most important features. The paper also presents the reasons that led to the downfall of both the Program Planning Budgeting System (PPBS) and the Policy and Expenditure Management System (PEMS). The paper goes on to argue that the recently introduced approach—labeled the Expenditure Review Committee (ERC)—is also unlikely to meet expectations. It also provides an historical context for understanding why each particular approach was adopted.
Low parasitoid success on a myrmecophilous host is maintained in the absence of ants
Authors: Sloggett John J. , Webberley K. Mary , Majerus Michael E. N. 
Published: February 2004

Abstract.  1. Studies of Dinocampus coccinellae, a parasitoid of ladybird beetles, have generally shown congruence between field parasitism rates of different host species and parasitoid preference and/or host suitability in the laboratory, suggesting that host intrinsic factors rather than habitat‐related extrinsic factors are of greatest importance in determining D. coccinellae occurrence.2. The myrmecophilous Coccinella magnifica exhibits much lower D. coccinellae prevalence in the field than most other Coccinella species: it has been suggested that this is a manifestation of enemy‐free space provided by the predatory Formica rufa group ants with which the C. magnifica occurs.3. Coccinella magnifica collected at the same time and locality as parasitised Coccinella septempunctata were unparasitised by D. coccinellae. In the laboratory, in the absence of ants, although the parasitoid attacked C. magnifica as readily as C. septempunctata, C. magnifica was not parasitised successfully.4. Such results are consistent with those from other ladybirds and C. magnifica does not now benefit directly from any putative D. coccinellae‐free space provided by aggressive ants. Because its close relatives exhibit high levels of D. coccinellae parasitism, C. magnifica may be useful in determining some elements important in the evolution of host protection against parasitoid attack.
Development of the solitary endoparasitoid Microplitis demolitor: host quality does not increase with host age and size
Authors: Harvey Jeffrey A. , Bezemer T. Martijn , Elzinga Jelmer A. , Strand Michael R. 
Published: February 2004

Abstract.  1. Many studies examining the relationship between host size, an index of host quality, and parasitoid fitness use development time and/or adult parasitoid size as currencies of fitness, while ignoring pre‐adult mortality. Because the physiological suitability of the host may vary in different stages, sizes, or ages of hosts, a misleading picture of host quality may therefore be obtained in cases where fitness is based on only one or two developmental traits.2. The development of the solitary koinobiont endoparasitoid Microplitis demolitor is examined in different larval age‐classes of its host the soybean looper Pseudoplusia includens. Hosts were parasitised on days 1–8 after hatching from the egg, and development time, adult body size, and mortality of the parasitoid were compared.3. A comparison of larval growth trajectories (using dry body mass) of M. demolitor revealed that parasitoid larvae attained over twice as much body mass in old hosts than in younger hosts. Similarly, adult parasitoid size at eclosion generally increased with host size, although parasitoids developing in smaller hosts lost a much lower proportion of mass between pupation and eclosion.4. Overall egg‐to‐adult development was most rapid in intermediate‐aged hosts, and longer in hosts at opposite ends of the age continuum. Moreover, parasitoid mortality varied non‐linearly with host stage, and was generally higher in very young and older hosts.5. Based on these results and other empirical data for koinobionts, it is argued that fitness functions in this group of parasitoids are not simply a positive function of host size or age, but instead may be distinctly dome‐shaped, both patterns reflecting the degree of physiological and nutritional compatibility between the two organisms.
Wedged between bottom‐up and top‐down processes: aphids on tansy
Authors: Stadler Bernhard 
Published: February 2004

Abstract. 1. Many species of aphids exploit a single host‐plant species and have to cope with changing environmental conditions. They often vary greatly in abundance even when feeding on the same host. In a field experiment, the bottom‐up (plant quality/patch type frequency) and top‐down (ant attendance/predation) effects on the abundance of four species of aphids feeding on tansy (Tanacetum vulgare) were tested using a full factorial design. In addition, a model was used to examine these patch characteristics for their relative effects on the population dynamics and abundance of different aphid species.2. Aphid numbers changed significantly depending on the quality of the host plant and the presence/absence of attending ants. The obligate myrmecophile,Metopeurum fuscoviride, was abundant on high‐quality plants, while on poor quality plants or on plants without attending ants these aphids did not survive until the end of the experiment. The facultative myrmecophiles,Aphis fabaeandBrachycaudus cardui, and the unattended aphid species,Macrosiphoniella tanacetaria, all reached similar peak population densities, butM. tanacetariadid best in poor quality patches.3. Natural enemies reduced aphid numbers, but those species feeding on high‐quality plants survived longer than those on poor‐quality plants, which existed only for a short period of time, especially when associated with ants. Losses due to migration of winged morphs and mortality caused by parasitoids were insignificant.4. Varying the frequency of different patch types in a model indicates that different degrees of associations with ants are favoured in different environments. If the proportion of high‐quality patches in a habitat is large, obligate myrmecophiles do best. On increasing the number of poor‐quality patches, unattended species become more abundant.5. The results suggest that, in spite of large species specific differences in growth rates, degree of myrmecophily or life cycle features, the temporal and spatial variability in top‐down and bottom‐up forces differentially affects aphid species and allows the simultaneous exploitation of a shared host‐plant species.
Lack of detrimental effects of nitric oxide inhibition in bile duct‐ligated rats with hepatic encephalopathy
Authors: Chan C.‐Y. , Huang S.‐W. , Wang T.‐F. , Lu R.‐H. , Lee F.‐Y. , Chang F.‐Y. , Chu C.‐J. , Chen Y.‐C. , Chan C.‐C. , Huang H.‐C. , Lee S.‐D. 
Published: February 2004

AbstractBackground  The pathogenetic mechanisms of hepatic encephalopathy (HE) are not fully understood. Vasodilatation induced by nitric oxide (NO) may be involved in the development of HE. There is no comprehensive data concerning the effects of NO inhibition on HE in chronic liver disease.Methods  Male Sprague‐Dawley rats weighing 240–270 g at the time of surgery were selected for experiments. Secondary biliary cirrhosis was induced by bile duct ligation (BDL). Counts of movements were compared between BDL rats and rats receiving a sham operation. In another series of experiments, BDL rats received either Nω‐nitro‐L‐arginine methyl ester (L‐NAME, 25 mg kg−1 day−1 in tap water) or tap water (control) from the 36th to 42nd days after BDL. Besides motor activities, plasma levels of tumour necrosis factor (TNF)‐α and nitrate/nitrite, liver biochemistry tests and haemodynamics were determined after treatment.Results  Compared with the sham‐operated rats, the total, ambulatory and vertical movements were significantly decreased in the BDL rats (P ≤ 0·001). The L‐NAME group had a significantly higher mean arterial pressure than that of the control group (119·0 ± 2·5 mmHg vs. 97·3 ± 2·8 mmHg, P = 0·002). However, the counts of motor activities, plasma levels of TNF‐α and nitrate/nitrite, and serum biochemistry tests were not significantly different between the L‐NAME and control groups.Conclusions  Bile duct ligation may induce HE evidenced by a decrease in motor activities. However, chronic L‐NAME administration did not have significantly detrimental or therapeutic effects on the severity of encephalopathy in BDL rats.
High levels of desmosines in urine and plasma of patients with pseudoxanthoma elasticum
Authors: Annovazzi L. , Viglio S. , Gheduzzi D. , Pasquali‐Ronchetti I. , Zanone C. , Cetta G. , Iadarola P. 
Published: February 2004

AbstractBackground  Pseudoxanthoma elasticum (PXE), a rare heritable disorder caused by mutations of the ABCC6 gene, is characterized by fragmentation and mineralization of elastic fibres. We determined the extent of degradation of elastin by measuring and comparing the amount of desmosines in plasma and urine of PXE patients, healthy carriers and normal subjects.Methods  Using capillary electrophoresis with laser‐induced fluorescence detection (CE‐LIF) we measured the amount of desmosines in the urine of 46 individuals (14 PXE patients, 17 healthy carriers and 15 controls) and in the plasma of 56 subjects (18 PXE patients, 23 healthy carriers and 15 controls). Pseudoxanthoma elasticum patients and carriers were identified by clinical, structural and molecular biology analyses.Results  The urinary excretion of desmosines was two‐fold higher in PXE patients than in controls (P < 0·01); the values for healthy carriers were intermediate between those of PXE patients and controls. A very similar trend between patients and their relatives was observed for plasma desmosines. There was a significant correlation between the amount of the desmosines in plasma and urine. Moreover, a positive correlation was observed between urinary desmosine content and age of the patients as well as between urinary desmosine content and severity of clinical manifestations.Conclusions  Both the urinary and plasma desmosine concentrations indicate that elastin degradation is higher in PXE patients and, to a lesser extent, in healthy carriers than in normal subjects. Data seem to indicate that the amount of elastin breakdown products correlates with the age of patients as well as with the severity of the disease.
α1 Adrenoreceptors Mediate The Stimulatory Effects of Oestrogen On Stress‐Related Hypothalamic‐Pituitary‐Adrenal Activity in The Female Rat
Authors: Viau V. , Meaney M. J. 
Published: February 2004

AbstractVariation in challenge‐induced adrenocorticotropin hormone (ACTH) release over the oestrous cycle occurs in response to fluctuations in circulating concentrations of oestrogen and progesterone. However, how these ovarian steroids interact to regulate the principal ACTH cosecretagogues, corticotropin‐releasing hormone (CRH) and arginine vasopressin is not understood. Here, we measured median eminence CRH and vasopressin content in intact cycling female rats, and in ovariectomized (OVX) females steroid‐replaced in a manner that approximates the relative release patterns of oestrogen and progesterone seen over the oestrous cycle. Intact cycling females showed significantly higher median eminence CRH and vasopressin concentrations during proestrous and oestrous compared to the diestrous phase. In OVX rats, a single 10 µg injection of oestrogen failed to mimic this increase in median eminence CRH and vasopressin. However, this dose significantly elevated CRH and vasopressin content in OVX rats previously exposed to diestrous concentrations of oestrogen and progesterone. Moreover, oestrogen priming enhanced restraint‐induced depletion of CRH and vasopressin from the median eminence, but only against a background of low oestrogen and progesterone replacement. Oestrogen‐induced elevations in median eminence vasopressin (but not CRH) content were reduced by peripheral administration of the α1 adrenoreceptor antagonist prazosin. Finally, plasma ACTH concentrations following central injection of the α1 receptor agonist, phenylephrine, were significantly higher in rats during proestrous compared to diestrous. These results indicate that the stimulatory effect of oestrogen on both the expression and stress‐induced release of ACTH cosecretagogues is exerted only against a background of low oestrogen and progesterone levels, and is mediated, in part, via the α1 adrenoreceptor.
Central and Peripheral Immunoreactivity of Melanin‐Concentrating Hormone in Hypothalamic Obese and Lactating Rats
Authors: Sun G. , Tian Z. , Murata T. , Narita K. , Honda K. , Higuchi T. 
Published: February 2004

AbstractMelanin‐concentrating hormone (MCH) is believed to be an important orexigenic peptide mainly localized in the lateral hypothalamic area. Its involvement in the hyperphagia induced by hypothalamic lesions and lactation remains unclear. In this study, we investigated MCH immunoreactivity in the hypothalamus using immunohistochemistry and MCH concentration in the peripheral circulation using an enzyme immunoassay in rats with a lesion in the ventromedial hypothalamus or the paraventricular nucleus, and in lactating rats. Bilateral lesions of the ventromedial or paraventricular nuclei were performed using an electrolytic method. Quantification of immunoreactivity by image analysis revealed that the number and mean staining intensity of MCH‐immunoreactive neurones in the lateral hypothalamic area and the zona incerta were significantly decreased by both types of lesions compared to sham controls, whereas circulating MCH concentration was not significantly different on day 7 postlesion. By contrast, in lactating rats on days 11–12 postpartum, the expression of MCH in the lateral hypothalamic area and the zona incerta was significantly increased compared to nonlactating controls. Circulating MCH concentration was not changed in lactating rats. These results suggest that hyperphagia induced by lactation, but not hypothalamic lesion, might be induced by excessive expression of MCH in the lateral hypothalamic area and the zona incerta.