bluuebunny/crossref_metadata_2025_split huggingface dataset:
Facilitation of renal autoregulation by angiotensin II is mediated through modulation of nitric oxide
Authors: Guan Z. , Willgoss D. A. , Matthias A. , Manley S. W. , Crozier S. , Gobe G. , Endre Z. H. 
Published: September 2003

AbstractAims: This study was designed to investigate the influence of angiotensin II (Ang II) and nitric oxide (NO) on autoregulation of renal perfusion.Methods: Autoregulation was investigated in isolated perfused kidneys (IPRK) from Sprague‐Dawley rats during stepped increases in perfusion pressure.Results: Ang II (75–200 pM) produced dose‐dependent enhancement of autoregulation whereas phenylephrine produced no enhancement and impaired autoregulation of GFR. Enhancement by Ang II was inhibited by the AT1 antagonist, Losartan, and the superoxide scavenger, Tempol. Under control conditions nitric oxide synthase (NOS) inhibition by 10 μm N‐omega‐nitro‐ιl‐arginine methyl ester (ιl‐NAME) facilitated autoregulation in the presence of non‐specific cyclooxygenase (COX) inhibition by 10 μm indomethacin. Both COX and combined NOS/COX inhibition reduced the autoregulatory threshold concentration of Ang II. Facilitation by 100 pm Ang II was inhibited by 100 μm frusemide. Methacholine (50 nm) antagonised Ang II‐facilitated autoregulation in the presence and absence of NOS/COX inhibition. Infusion of the NO donor, 1 μm sodium nitroprusside, inhibited ιl‐NAME enhancement of autoregulation under control conditions and during Ang II infusion.Conclusions: The results suggest than an excess of NO impairs autoregulation under control conditions in the IPRK and that endogenous and exogenous NO, vasodilatory prostaglandins and endothelium‐derived hyperpolarizing factor (EDHF) activity antagonise Ang II‐facilitated autoregulation. Ang II also produced a counterregulatory vasodilatory response that included prostaglandin and NO release. We suggest that Ang II facilitates autoregulation by a tubuloglomerular feedback–dependent mechanism through AT1 receptor‐mediated depletion of nitric oxide, probably by stimulating generation of superoxide.
Effects of exercise on platelet and aortic functions in aged rats
Authors: Tanaka Y. , Hashimoto M. , Masumura S. 
Published: September 2003

AbstractAim and methods:  To assess age‐ and exercise‐related changes in platelet aggregation, we measured the magnitude of platelet aggregation with a four‐channel aggregometer, plasma and aortic polyunsaturated fatty acids by gas chromatography and related prostanoids with a reagent kit in young and aged non‐exercised and in aged exercised rats.Results:  Platelet aggregation in platelet‐rich plasma induced by ADP (5 μm) in the primary wave increased with age. In the non‐exercised groups, the basal levels of thromboxane B2 in platelet‐rich plasma increased in aged rats compared with young rats. In aged exercised rats, the basal levels of 6‐keto‐prostaglandin F1α in platelet‐rich plasma were stimulated and those of thromboxane B2 were depressed, compared with non‐exercised aged rats. The plasma levels of eicosapentaenoic acid and docosahexaenoic acid increased with age. Only aortic eicosapentaenoic acid in the aged group increased by exercise. In the aged non‐exercised and exercised groups, the aortic, but not the plasma, levels of eicosapentaenoic acid correlated inversely with the basal levels of thromboxane B2 in platelet‐rich plasma (r = −0.53, P < 0.05) and associated negatively with the magnitudes of platelet aggregation induced by ADP (5 μm) (r = −0.47, P < 0.05).Conclusion:  These findings suggest that exercise in aged rats increases aortic eicosapentaenoic acid concentrations, which in turn depress the basal levels of thromboxane, B2 in platelet‐rich plasma to modulate platelet aggregation.
Endotoxin‐induced shock in the pig – limited effects of low and high concentrations of inhaled nitric oxide
Authors: Middelveld R. J. M. , Alving K. 
Published: September 2003

AbstractAim:  This study was carried out to study the prophylactic effects of inhalation of nitric oxide (NO) before and during the induction of endotoxic shock.Methods:  Eighteen anaesthetized pigs received an infusion of 10–20 μg kg−1 endotoxin during 2 h after pre‐treatment with the cortisol‐synthesis inhibitor metyrapone. Three groups were tested (n = 6 each) and received 0, 0.2 or 20 ppm inhaled NO from 30 min before start of endotoxin infusion until 4 h after start of endotoxin. Both 0.2 and 20 ppm NO were able to improve blood gas values.Results:  Area above curve values of arterial P2/FiO2 from 0 to 4 h were 0.83 ± 0.09 kPa h (control), 0.78 ± 0.22 (0.2 ppm NO, non‐significant) and 0.31 ± 0.06 (20 ppm NO, P < 0.01, Mann–Whitney U‐test, compared to control). Area under curve values of PCO2 from 0 to 4 h were 3.96 ± 0.66 kPa h (control), 1.20 ± 0.46 (0.2 ppm NO, P < 0.05, Mann–Whitney U‐test, compared to control) and 2.78 ± 1.06 (20 ppm NO group, non‐significant). The increase in pulmonary arterial pressure (PAP) was partly prevented by 20 ppm NO, but not by 0.2 ppm NO at 4 h. Inhaled NO did not affect the levels of BAL fluid total protein, tumour necrosis factor‐α, interleukin‐8 and neutrophil counts.Conclusions:  The addition of a high (20 ppm), but not a low (0.2 ppm), concentration of NO to the inhaled air during endotoxin shock improves arterial oxygen tension and reduces pulmonary artery pressure. Neither dose affects lung mechanics or inflammatory indices, in spite of being given prophylactically.
A physiological role for protoporphyrin IX photodynamic action in the rat Harderian gland?
Authors: Cui Z. J. , Zhou Y. D. , Satoh Y. , Habara Y. 
Published: September 2003

AbstractAims: The lipid‐secreting exocrine Harderian gland contains a large amount of porphyrins (mainly protoporphyrin IX, PPIX) in the glandular cells, the physiological significance of which is rather poorly understood.Methods: In the present study, the possibility of using Fura‐2 to measure intracellular calcium ([Ca2+]c) changes in these cells was assessed.Results: It was found that when Fura‐2‐loaded cells were excited by light at 340/380 nm, [Ca2+]cincreased spontaneously, indicating a photodynamic action powered by light at 340/380 nm. In contrast, with the visible spectrum calcium probe Fluo‐3 (λex = 475 nm), carbachol at 10 μminduced [Ca2+]cincrease; [Ca2+]cdid not change without carbachol stimulation. Brief illumination with light at 340/380 nm induced a large [Ca2+]cincrease in Fluo‐3‐loaded cells. Photodynamic stimulation of [Ca2+]cincrease was confirmed with an exogenous photosensitizer sulphonated aluminium phthalocyanine (SALPC) and visible light (>580 nm). The wavelength‐dependence of the [Ca2+]cincrease correlates well with the excitation spectrum of the isolated Harderian glandular cells.Conclusion:These data suggest that PPIX present in rat Harderian glandular cells plays the role of a photosensitizer which upon activation by UVA and blue components of daylight and subsequent singlet oxygen generation, triggers [Ca2+]cincrease and secretory response. The PPIX photodynamic action may also play a potential role in photic entrainment of the central circadian clock.
NOS 3 subcellular localization in the regulation of nitric oxide production
Authors: Sullivan J. C. , Pollock J. S. 
Published: September 2003

AbstractEndothelium‐derived nitric oxide (NO) is a key signalling molecule in the maintenance of cardiovascular health. Endothelial NO synthase (NOS 3), which catalyses the formation of NO, is targeted to the plasma membrane by dual acylation. In vitro studies suggest that membrane localization of NOS 3 is an important regulatory element of NO production. Dysfunction of the vascular endothelium and a decrease in NO bioavailability is associated with the development and progression of a number of cardiovascular diseases, including hypertension. Our laboratory has previously published that in salt‐dependent hypertension there is an altered localization of NOS 3, with an increase in cytosolic expression. These data have led us to question whether the increased cytosolic NOS 3 expression is a form of compensation for endothelial dysfunction in hypertension, or an indicator and contributing factor to endothelial dysfunction. This review will outline the importance of subcellular localization in the regulation of NOS 3 in vitro, the role of NOS 3 in endothelial dysfunction associated with salt‐dependent hypertension, and the potential physiological consequences of altered NOS 3 localization in vivo.
From molecules to mammals: what's NOS got to do with it?
Authors: Mungrue I. N. , Bredt D. S. , Stewart D. J. , Husain M. 
Published: September 2003

AbstractNitric oxide synthases (NOSs) generate nitric oxide (NO) and the by‐product l‐citrulline, via the catalytic combination of l‐arginine and molecular oxygen. In mammals, there are three NOS genes: nNOS (NOS1), iNOS (NOS2) and eNOS (NOS3). The molecular structure, enzymology and pharmacology of these enzymes have been well defined, and reveal critical roles for the NOS system in a variety of important processes. The studies of NOS enzymes using knockout and transgenic mouse models have provided an invaluable contribution, highlighting critical roles in neuronal, renal, pulmonary, gastro‐intestinal, skeletal muscle, reproductive and cardiovascular biology. This review will outline the data gleaned from complementary knockout and transgenic over‐expression models in mice, and focus on the interactions between NOS enzymes and pathophysiology of the vascular system. These studies are a paradigm for the near future, which will involve the translation of an enormous amount of genomic data into physiological insights that penetrate the realms of both health care and biology.
Caveolae, caveolin and cav‐p60 in smooth muscle and renin‐producing cells in the rat kidney
Authors: Voldstedlund M. , Thuneberg L. , Tranum‐Jensen J. , Vinten J. , Christensen E. I. 
Published: September 2003

AbstractAims: In vascular smooth muscle cells caveolae are important for signalling mechanisms regulating vascular contraction. In smooth muscle layer of the renal afferent arteriole juxtaglomerular cells (JG cells) are non‐contractile renin producing cells that have the capacity to change their phenotype into smooth muscle cells and back again by metaplastic transformation.Signalling mechanisms in JG cells are not fully understood and we therefore investigated if caveolae were present, and thereby could be involved as integrators of cellular signalling in both of these phenotypes of smooth muscle cells.Methods: Using electron microscopy we compared the number of caveolae in JG cells and smooth muscle cells in the afferent arteriole of the rat kidney. The expression of caveolin and cav‐p60 was examined using a combination of immunogold electron microscopy and immunofluorescence microscopy.Results: We found that JG cells have sixfold less caveolae per cell surface sectional length than smooth muscle cells. The expression of cavolin‐1 and cav‐p60 correlated with the number of caveolae. An examination of the general distribution of caveolae, cav‐p60 and caveolins in the rat kidney showed that cav‐p60, like caveolin‐1, is a specific maker of caveolae.Conclusion: The number of caveolae in JG cells is very low, and this makes it unlikely that caveolae are of major importance for the renin secretion specific for JG cells.
Muscle fibre size and capillarity in Korean diving women
Authors: Bae K. A. , An N. Y. , Kwon Y. W. , Kim C. , Yoon C. S. , Park S. C. , Kim C. K. 
Published: September 2003

AbstractAim:  Effects of prolonged habitual cold‐water immersion on fibre size and capillarity in vastus lateralis muscle were studied in human beings. The hypothesis tested in the present study was that cold acclimatized human skeletal muscle would have reduced muscle fibre size and higher capillarity, favouring the idea of efficacy of recruitment under cold environment.Methods:  Ten women breath‐hold divers (BHDs) and 10 active women (controls CONs) participated in this study. Muscle biopsy was obtained from vastus lateralis and determined fibre type composition and capillary density.Results: A major finding was that all BHDs revealed a markedly smaller cross‐sectional area (CSA) in all fibre types than the CONs, or even than any other morphological data reported in previous investigations. Furthermore, mean CSA of type II fibre (range 1205–2766 μm2) was much smaller than type I fibre (2343–4327 μm2). The number of capillaries per fibre in different fibre types in the BHDs was higher than in the CONs (P < 0.001), and diffusional area was smaller in type II fibres than in type I fibres (P < 0.001). The BHDs and the CONs have similarity in the percentage of type I fibres, but type II fibre was predominant in both groups. Interestingly the proportion of type IIx fibre in the BHDs was higher (31%) than in the CONs (22%). No significant difference was found in the thigh circumference between the groups.Conclusion:  The present study demonstrates that prolonged habitual cold‐water immersion may induce a decrease in fibre size and an increase in capillarity in human skeletal muscle.
Lack of efficacy of ‘naked’ small interfering RNA applied directly to rat brain
Authors: Isacson R. , Kull B. , Salmi P. , Wahlestedt C. 
Published: September 2003

AbstractThe intrastriatal infusions of ‘naked’ small interfering RNA (siRNA) targeted to dopamine D1 receptors (1.0–10.0 nmol over 3 days) did not reduce dopamine D1 receptor messenger RNA levels or receptor protein, assessed by [125I] SCH 23982 binding in intact rats. This was in contrast to results in vitro where a 76% reduction in dopamine D1 receptor ligand binding could be observed.Conclusion:The results suggest that synthetic siRNA, when applied directly to rat brain, is not capable of inducing RNA interference.
Role of Ca2+‐activated Cl− current during proarrhythmic early afterdepolarizations in sheep and human ventricular myocytes
Authors: Verkerk A. O. , Tan H. L. , Kirkels J. H. , Ravesloot J. H. 
Published: September 2003

AbstractObjectives:  The proarrhythmic early afterdepolarizations (EADs) during phase‐2 of the cardiac action potential (phase‐2 EADs) are associated with secondary Ca2+‐release of the sarcoplasmic reticulum. This makes it probable that the Ca2+‐activated Cl− current [ICl(Ca)] is present during phase‐2 EADs. Activation of ICl(Ca) during phase‐2 of the action potential will result in an outwardly directed, repolarizing current and may thus be expected to prevent excessive depolarization of phase‐2 EADs. The present study was designed to test this hypothesis.Methods and Results:  The contribution of ICl(Ca) during phase‐2 EADs was studied in enzymatically isolated sheep and human ventricular myocytes using the patch‐clamp methodology. EADs were induced by a combination of a low stimulus frequency (0.5 Hz) and exposure to 1 μm noradrenaline. In sheep myocytes, the ICl(Ca) blocker 4,4′‐diisothiocyanostilbene‐2,2′‐disulfonic acid (DIDS, 0.5 mm) abolished phase‐1 repolarization of the action potential in all myocytes tested. This indicates that ICl(Ca) is present in all sheep myocytes. However, DIDS had no effect on phase‐2 EAD characteristics. In human myocytes, DIDS neither affected phase‐1 repolarization nor phase‐2 EAD characteristics.Conclusion:  In sheep ventricular myocytes, but not in human ventricular myocytes, ICl(Ca) contributes to phase‐1 repolarization of the action potential. In both sheep and human myocytes, ICl(Ca) plays a limited role during phase‐2 EADs.
Trafficking and activation of eNOS in epithelial cells
Authors: Ortiz P. A. , Garvin J. L. 
Published: September 2003

AbstractIn mammalian cells, formation of nitric oxide (NO) is catalysed by a family of enzymes termed NO synthases (NOS). There are three isoforms of this enzyme, NOS I, II and III. NOS III was originally cloned and identified in endothelial cells; thus this isoform is commonly called endothelial NOS (eNOS). The physiological role of NO produced by eNOS has been documented in most organs, including the brain, lung, cardiovascular system, kidney, liver, gastrointestinal tract and reproductive organs. The bioavailability of NO in these tissues is determined by the balance between its rate of production and degradation. The rate of NO production by eNOS is ultimately dependent on the activity of the enzyme. In the past years, co‐ and post‐translational modifications such as myristoylation, palmitoylation, phosphorylation, protein–protein interactions and subcellular localization have been shown to play an important role in determining eNOS activity. In order to maintain specificity, the production of most signalling molecules occurs in an organized spatial and temporal pattern. Spatial localization of eNOS has been shown to be regulated by different mechanisms that control its targeting from the Golgi apparatus to the plasma membrane, correct compartmentalization within the membrane, and internalization from the plasma membrane to the cytoplasm after activation. Thus, regulated localization and trafficking of eNOS may be essential in regulating enzyme activity and maintaining the spatial and temporal organization of NO signalling in different cell types.
Identification and physical mapping of genes expressed in the corpus luteum in cattle1
Authors: Bønsdorff T. , Eggen A. , Gautier M. , Åsheim H.‐C. , Rønningen K. , Lingaas F. , Olsaker I. 
Published: September 2003

SummaryA representational difference analysis was performed to identify genes expressed in the corpus luteum of cattle. The corpus luteum is an ovarian structure that is essential for the establishment and maintenance of pregnancy. Knowledge of gene expression and function of corpus luteum will be important to improve fertility in humans and domestic animals. Housekeeping genes were removed from the corpus luteum representation (tester) using skeletal muscle as the subtracting agent (driver). A total of 80 clones of the final subtraction product were analysed by sequencing and 11 new bovine gene sequences were identified (pBTCL1–11). The sequences were mapped to segments of 10 different chromosomes using a somatic cell hybrid panel and a radiation hybrid panel. With one exception the locations are in agreement with published comparative maps of cattle and man. Expression in corpus luteum was verified by RT–PCR for all the 11 clones.
Chromosomal mapping, sequence and transcription analysis of the porcine fertilin beta gene (ADAM2)1
Authors: Day A. E. , Quilter C. R. , Sargent C. A. , Mileham A. J. 
Published: September 2003

SummaryFertilin beta (ADAM2) forms a part of the heterodimeric surface protein fertilin, found on the plasma membrane of mammalian sperm, and has been implicated in the process of sperm–egg fusion. Analysis of cDNA products obtained from adult porcine testis mRNA has presented a sequence corresponding to 2620 bp of the ADAM2 gene. This sequence contained an open reading frame encoding a 735‐amino acid protein and homologous to ADAM2 genes known in other mammalian species. Polymerase chain reaction (PCR) analysis of genomic DNA showed that the 2620 bp of cDNA sequence comprises at least 21 exons and spans approximately 76 kb of genomic DNA, with its size and structure being relatively conserved between mouse, human and pig. Fluorescence in situ hybridization was used to map ADAM2 to chromosome 15 of the pig, using a bacterial artificial chromosome clone from the PigE BAC library. This finding is consistent with comparative mapping experiments performed between pig and human chromosomes. Analysis of nine mRNA samples, by reverse transcriptase‐PCR, from different porcine tissues has also suggested that expression of ADAM2 is limited to the testis, a finding that is consistent with other mammalian species.
Atypical squamous cells of undetermined significance: audit and the impact of potential litigation. Retrospective review of 682 cases
Authors: Scheiden R. , Wagener C. , Knolle U. , Dippel W. , Capesius C. 
Published: September 2003

For quality assurance purposes, the frequency of ‘abnormal’ cytological diagnoses of the non‐systematic National Cervical Cancer Screening Programme (NCCSP) was evaluated. In 1999, an unexpected high number of Class (Cl) III cases (i.e. atypical squamous cells of undetermined significance) was reported. The cytological and histological results were reviewed in order to detect a possible cause for this threefold increase. The abnormal Papanicolaou (PAP) smears examined by conventional methods from 1 January 1990 to 31 December 2002 were analysed. The smears of 682 cases diagnosed in 1999 with a Cl III category were reviewed in 2000 and correlated with the available histological diagnoses provided by the Central Department of Pathology.Of the 682 Cl III cases, 176 cases (26.1%) had no follow‐up, 314 cases (46.0%) had repeat cytology and 192 cases (28.2%) an histological correlate corresponding to 90 (46.9%) benign lesions, 78 (40.6%) squamous intraepithelial lesions, two (1%) invasive cervical cancers (one squamous and one glandular). Twenty‐two Cl III cases (11.5%) were histologically within normal limits. Retrospective smear review confirmed 330 Cl III diagnoses (48.3%), 127 cases (18.6%) were recategorized as Cl IIIG (i.e. atypical glandular cells of undetermined significance), 22 cases (3.2%) as Cl IIID (i.e. mild to moderate dysplasia) and six cases (0.9%) as Cl IVa (i.e. severe dysplasia and/or carcinoma in situ). A total of 197 original Cl III cases had to be reclassified in the Cl II category (28.9%), only two cases showing mild and moderate dysplasia on histology. Thus, 195 cases (28.6%) comprised cytological overdiagnoses. The Cl III category being, by definition, a delicate and often subjective diagnosis, all external influences such as pressure of litigation should be avoided to reduce cytological overdiagnoses as a result of an unnecessary ‘fear‐factor’.
Host shifting by Operophtera brumata into novel environments leads to population differentiation in life‐history traits
Authors: Vanbergen Adam J. , Raymond Ben , Pearce Imogen S. K. , Watt Allan D. , Hails Rosie S. , Hartley Susan E. 
Published: September 2003

Abstract.  1. Operophtera brumata L. (Lepidoptera: Geometridae), a polyphagous herbivore usually associated with deciduous trees such as oak Quercus robur L., has expanded its host range to include the evergreen species heather Calluna vulgaris (L.) Hull and, most recently, Sitka spruce Picea sitchensis (Bong.) Carrière.2. Phenology, morphology, and survival of O. brumata were measured at several life‐history stages in populations from the three different host plant communities sampled from a range of geographical locations. The data were used to test for population differences, reflecting the marked differences in host‐plant secondary chemistry, growth form, and site factors such as climate. The hypothesis that spruce‐feeding populations originated from populations feeding on moorland, commonly sites of coniferous afforestation, was also tested.3. Altitude, not host plant species, was the major influence on the timing of adult emergence. An effect of insect population independent of altitude was found, implying that additional unidentified factors contribute to this phenological variation. Larval survival and adult size varied between populations reared on different host plant species. Survival of larvae was affected negatively when reared on the novel host plant, Sitka spruce, versus the natal plant (oak or heather) but oak and heather‐sourced insects did not differ in survivorship on Sitka spruce.4. Host range extension into novel environments has resulted in population differentiation to the local climate, demonstrating that host shifts pose challenges to the herbivore population greater than those offered by the host plant alone. The hypothesis that Sitka spruce feeding populations have arisen predominantly from moorland feeding populations was not supported.