bluuebunny/crossref_metadata_2025_split huggingface dataset:
An assessment of microbial coronal leakage in teeth root filled with gutta‐percha and three different sealers
Authors: CHAILERTVANITKUL P. , SAUNDERS W. P. , MACKENZIE D. 
Published: September 2007

SummaryThe aim of this in vitro study was to determine the effect of three different root canal sealers on the bacterial penetration of obturated root canals. Eighty extracted human teeth with straight, single root canals were prepared using the modified double‐flared technique with balanced force under copious irrigation until the master apical file was size 40. The teeth were divided randomly into experimental groups (60 teeth) and control groups (20 teeth). Twenty experimental teeth each were obturated by lateral condensation of cold gutta‐percha with AH26, Apexit or Tubliseal EWT sealer. In the control groups, 10 teeth were obturated using the same technique with AH26, Apexit or Tubliseal EWT sealer. These teeth were completely sealed to serve as negative controls. The remaining 10 teeth were not obturated and served as positive controls. The root surface of each tooth, except the apical 2 mm, was sealed with nail varnish. The coronal part of each root canal was sealed with the cut end of a polypropylene tube and placed in a glass bottle containing sterile Todd‐Hewitt Broth (THB). Aliquots of 0.5 ml of THB were injected into the polypropylene tube and the model system was centrifuged at 168 g. An innoculum of Streptococcus sanguis in THB was added to the tube at 5‐day intervals and daily observations were made for bacterial growth in the apical reservoir for 90 days. AH positive control teeth showed bacterial penetration within 24 h and negative control teeth remained uncontaminated throughout the test period. Leakage through the experimental teeth varied from 7 to 86 days. There was no statistically significant difference (P>0.05) in leakage of the obturated canals between AH26, Apexit and Tubliseal EWT sealers.
Towards an understanding of the Of?p star HD 191612: optical spectroscopy
Authors: Howarth Ian D. , Walborn Nolan R. , Lennon Danny J. , Puls Joachim , Nazé Yaël , Annuk K. , Antokhin I. , Bohlender D. , Bond H. , Donati J.-F. , Georgiev L. , Gies D. , Harmer D. , Herrero A. , Kolka I. , McDavid D. , Morel T. , Negueruela I. , Rauw G. , Reig P. 
Published: September 2007

Abstract
We present extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe–O8fp). The Balmer and He i lines show strongly variable emission which is highly reproducible on a well-determined 538-d period. He ii absorptions and metal lines (including many selective emission lines but excluding He iiλ4686 Å emission) are essentially constant in line strength, but are variable in velocity, establishing a double-lined binary orbit with Porb= 1542 d, e= 0.45. We conduct a model-atmosphere analysis of the spectrum, and find that the system is consistent with a ∼O8 giant with a ∼B1 main-sequence secondary. Since the periodic 538-d changes are unrelated to orbital motion, rotational modulation of a magnetically constrained plasma is strongly favoured as the most likely underlying ‘clock’. An upper limit on the equatorial rotation is consistent with this hypothesis, but is too weak to provide a strong constraint.
Timing of Preovulatory LH Surge and Ovulation in Superovulated Sheep are Affected by Follicular Status at Start of the FSH Treatment
Authors: Veiga‐Lopez A , Encinas T , McNeilly AS , Gonzalez‐Bulnes A 
Published: September 2007

ContentsThe aims of this study were to evaluate the chronology of periovulatory events (oestrus behaviour, LH surge and ovulation) in 16 superovulated Manchega sheep and to determine whether follicular status at start of the FSH supply might affect their occurrence. Mean timing for onset of oestrus behaviour was detected at 28.1 ± 0.7 h after sponge withdrawal; the preovulatory LH surge and ovulation started at 37.2 ± 0.7 h and 65.4 ± 0.7 h after progestagen withdrawal, respectively. The intervals between oestrus, LH surge and ovulation were affected by a high individual variability, which might be the cause for reported decreased efficiency in embryo production. Current results also addressed the role of follicular status at start of the superovulatory treatment on the preovulatory LH surge and the ovulation. The interval LH surge‐ovulation was increased in ewes with a growing dominant follicle at starting the FSH treatment (32.3 ± 0.9 vs 28.6 ± 0.5 h, p < 0.05). The developmental stage of the largest follicle at starting the superovulatory treatment also affected occurrence of LH surge and ovulation; follicles in growing phase advanced the occurrence of the LH surge and ovulation when compared to decreasing follicles (33.0 ± 1.0 vs 43.5 ± 1.1 h, p < 0.05, for LH peak and 60.7 ± 1.1 vs 72.8 ± 1.2 h, p < 0.05, for ovulation). Thus, only ewes with growing follicles ovulated prior to 55 h after sponge withdrawal; conversely, no sheep with decreasing follicles ovulated earlier than 67 h, when an 85.7% of the ewes bearing growing follicles has ovulated at 63 h.
Effect of Aspiration Pressure during Oocyte Harvesting on Oocyte Recovery and in vitro Development of Ovine Oocytes
Authors: Morton KM , Maxwell WMC , Evans G 
Published: September 2007

ContentsOocytes from abattoir‐sourced ovine ovaries were aspirated from 2‐ to 4‐mm follicles using 25, 50 or 100 mmHg pressure and an aspiration pump, or a needle (20‐G) and syringe (2.5 ml) and subjected to in vitro maturation, fertilization and culture to determine the effect of aspiration pressure on the number and quality of oocytes recovered, and early embryonic development. Oocyte recovery rate was similar between groups (range: 57.1–73.1%; p > 0.05). The number and percentage of grade I and II oocytes recovered was reduced for 100 mm (24.5 ± 3.6 and 31.1 ± 6.1%) compared with 25 mm (51.4 ± 7.0 and 60.2 ± 7.8%) and 50 mm pressure (40.8 ± 5.6 and 50.3 ± 4.4%) and a syringe (40.3 ± 12.0 and 45.2 ± 2.1%; p < 0.05). Oocyte cleavage was similar for all groups at 24 (range: 30.9–49.6%) and 48 h post‐insemination (49.7–65.5%), but blastocyst formation (% cleaved oocytes) was lower for oocytes aspirated with 25 mm (37.8%) than 50 (69.2%) or 100 mm (67.2%) pressure, and a syringe (72.0%; p < 0.05). Embryo production efficiency (% of oocytes cultured developing to the blastocyst stage) was higher for oocytes aspirated with 50 mm (45.4%) and 100 mm pressure (43.8%) and a syringe (45.0%) than 25 mm pressure (18.8%; p < 0.05). These results demonstrate that the aspiration of ovine oocytes with an aspiration pressure of 50 mm, or aspiration with a needle and syringe are equally efficacious for the in vitro production of embryos.
Effects of hCG Stimulation on Hepatic Activities of Cytochromes P4502E1 and P4502A in Pubertal Male Pigs
Authors: Zamaratskaia G , Oskam IC , Ropstad E , Tajet H , Dahl E , Andresen Ø 
Published: September 2007

ContentsThe effects of human chorionic gonadotropin (hCG) stimulation on fat skatole concentrations and hepatic activities of cytochromes P4502E1 (CYP2E1) and P4502A (CYP2A) were studied in Landrace and Duroc breeds of entire male pigs. Pigs were divided into four groups: two control groups of each breed, without hCG stimulation (n = 20 for each breed), and two experimental groups of each breed, with hCG stimulation (n = 18 for each breed). Pigs were slaughtered 3 days after hCG stimulation and activities of CYP2E1 and CYP2A were measured in liver homogenate. Activities of both CYP2E1 and CYP2A were lower in hCG‐stimulated pigs than control pigs for both Landrace (p = 0.005 for CYP2E1, p = 0.016 for CYP2A) and Duroc breeds (p = 0.003 for CYP2E1, p = 0.001 for CYP2A), and skatole concentrations in fat were higher in the hCG‐stimulated pigs of both breeds (p < 0.01). For both control and hCG‐stimulated groups, Duroc pigs had lower skatole concentrations than Landrace pigs (p = 0.001 for both groups). The activity of CYP2E1 did not differ significantly between breeds in either the control group or the experimental group (p = 0.233 for control pigs and p = 0.210 for experimental pigs). However, whereas CYP2A activity did not differ significantly between breeds in the control groups (p = 0.181 for CYP2A), in the hCG‐stimulated groups, CYP2A activity was lower in Duroc pigs than in Landrace (p = 0.011). Based on these findings, we conclude that hCG stimulation can suppress hepatic CYP2E1 and CYP2A activities, probably through an increase in the levels of testicular steroids. Between‐breed variations in skatole levels in fat were not related to the activities of CYP2E1 and CYP2A.
Efficiency Assessment of a Swift Method to Enhance Substandard Viability Ram Ejaculates
Authors: Piperelis SG , Vafiadis D , Boscos CM , Brozos C , Kiossis E , Alexopoulos C 
Published: September 2007

ContentsSemen availability in ram semen processing facilities is of great importance for the genetic improvement of sheep. Accordingly, any method that would increase sperm viability in low viability ejaculates could be useful. In this study, the possibility of a glass beads filtration method by estimating the beads total surface provided (TSP) for adhesion of spermatozoa, was evaluated. Initially, two different TSP (102 and 154 cm2) achieved by various sizes of beads (1500, 2000 and 3000 μm) were tested and no significant difference in sperm viability improvement was noticed for the same TSP by different beads (p > 0.05). Next optimization tests were performed in which three different funnels were used for filtration at a standard TSP (154 cm2). The pear‐shaped funnel was found to be the most appropriate for filtration, as semen volume recovery and sperm viability improvement were more pronounced (p < 0.05). Finally, filtration tests were conducted with pear‐shaped funnels with different TSP (102 and 154 cm2) obtained by the aforementioned beads sizes (1500, 2000 and 3000 μm) in equal aliquots. Total surface provided of 102 cm2proved to be the more appropriate for filtration than 154 cm2, as shown by the significant improvement of sperm viability (p < 0.01) and the significantly higher filtrate semen volume (p < 0.05). In conclusion, ram sperm viability improvement by more than 20% of its initial value and semen volume recovery by more than 60%, along with the fact that the total filtration time did not exceed 6 min in any case, suggest that through further development this method could be successfully used during ram semen processing.
ROLE OF p38‐MITOGEN‐ACTIVATED PROTEIN KINASE IN ISCHAEMIC PRECONDITIONING IN RAT HEART
Authors: Bell James R , Eaton Philip , Shattock Michael J 
Published: September 2007

SUMMARY

Activation of p38‐mitogen‐activated protein kinase (MAPK) has been implicated in the signalling cascade leading to protection by ischaemic preconditioning. This, however, is controversial and there is a plethora of conflicting data in the literature. Although many experimental differences may contribute to this, two in particular may be confounding: (i) the failure to account for p38‐MAPK activation during aerobic perfusion; and (ii) the use of the anti‐oxidant dimethylsulphoxide (DMSO) as the vehicle for the commonly used p38‐MAPK inhibitor SB203580. We have investigated the effects of aerobic perfusion, ischaemia and preconditioning on p38‐MAPK activation. In addition, we have used water‐soluble SB203580 hydrochloride (SB203580.HCl) and DMSO to probe the role of p38‐MAPK in preconditioning and ischaemic injury.
Activation of p38‐MAPK in rat isolated hearts was assessed using a dual phosphospecific antibody during cannulation, aerobic perfusion and index, autolytic and preconditioned ischaemia. The effect of SB203580.HCl (10 mmol/L) in ischaemic preconditioning and ischaemia/reperfusion was tested using recovery of function and tetrazolium (TTC) staining as end‐points.
Aerobic perfusion induced rapid activation (34% of maximal ischaemia‐induced increase; P < 0.05) of p38‐MAPK after 2 min that returned to baseline after 30 min. Index, autolytic and preconditioned ischaemia activated p38‐MAPK, with index ischaemia peaking after 15 min (520% of basal; P < 0.05) before declining. SB203580.HCl blocked p38‐MAPK activity, but did not block ischaemic preconditioning when bracketing the trigger phase and was not protective when given during ischaemia.
In the rat isolated heart, activation of p38‐MAPK is neither a unique feature of preconditioning nor a prerequisite. Previous studies using SB203580 may have been complicated by failure to account for the activation of p38‐MAPK by the protocol itself and the anti‐oxidant properties of the most commonly used vehicle DMSO.
REGULATION OF ENDOTHELIAL NITRIC OXIDE SYNTHASE: INVOLVEMENT OF PROTEIN KINASE G 1β, SERINE 116 PHOSPHORYLATION AND LIPID STRUCTURES
Authors: John Theresa A , Ibe Basil O , Raj J Usha 
Published: September 2007

SUMMARY

Endothelial nitric oxide synthase (NOS3) is important for vascular homeostasis. The role of protein kinase G (PKG) in regulation of NOS3 activity was studied in primary cultures of newborn lamb lung microvascular endothelial cells (LMVEC).
We determined the presence of PKG in fetal and neonatal LMVEC as well as subcellular localization of PKG isoforms in the neonatal cells by fluorescence immunohistochemistry. We used diaminofluorescein (DAF) fluorophore to measure nitric oxide (NO) production from neonatal LMVEC. We confirmed that NO measured was from constitutive NOS3 by inhibiting it with NOS inhibitors.
To identify a role for PKG in basal NO production, we measured NO release from LMVEC cells using 4‐amino‐5‐methylamino‐2′,7′‐difluorofluorescein (DAF‐FM; 0.5–0.8 µmol/L) with and without prior stimulation with the PKG activator 8‐bromo‐cGMP (8‐Br‐cGMP; 0.3 and 3 µmol/L) or prior PKG inhibition with β‐phenyl‐1,N2‐etheno‐8‐bromoguanosine‐3′,5′‐cyclic monophosphorothionate (BPC; 0.3 and 3 µmol/L). With the same drugs, we determined the role of PKG on cellular expression of NOS3 and serine 116 phosphorylated NOS (pSer116‐NOS) by qualitative and quantitative immunofluorescence assays, as well as western blotting.
Because PKG 1β was distributed throughout the cytosol in a punctate expression, we used 2 mmol/L cyclodextrin, a cholesterol extractor, to determine a role for lipid vesicles in PKG regulation of NO production.
Protein kinase G 1β gave a punctate appearance, indicating its presence in intracellular vesicles. Nitric oxide production decreased by approximately 20% with 300 nmol/L and 3 µmol/L 8‐Br cGMP (P < 0.05) and increased by 20.8 ± 3.7% with 3 µmol/L BPC (P < 0.001), indicating that both stimulated and basal PKG activity has inhibitory effects on basal NOS3 function. Nitric oxide synthase immunofluorescence and immunoblot expression were decreased and pSer116‐NOS immunofluorescence was increased by 800 nmol/L 8‐Br‐cGMP and 170 µmol/L (Z)‐1‐[2‐(2‐aminoethyl)‐N‐(2‐ammonio‐ethyl)amino]diazen‐1‐ium‐1, 2‐diolate (DETANONOate). The effect of cyclodextrin indicated that cholesterol extraction interfered with PKG inhibition of NOS. Further examination of pSer116‐NOS by immunohistochemistry showed it abundant in the endoplasmic reticulum and colocalized with PKG 1β, especially in nuclear vesicles.
We conclude that endothelial PKG is involved in endogenous regulation of basal NOS3 activity with the involvement of lipid structures, the endoplasmic reticulum and the nucleus. Protein kinase G 1β is colocalized with pSer116‐NOS, indicating that PKG action may involve serine 116 phosphorylation on NOS.
INFLUENCE OF SALT ON SUBCELLULAR LOCALIZATION OF NITRIC OXIDE SYNTHASE ACTIVITY AND EXPRESSION IN THE RENAL INNER MEDULLA
Authors: Sullivan Jennifer C , Smart Eric J , Pollock David M , Pollock Jennifer S 
Published: September 2007

SUMMARYThe aims of this study were: (i) to characterize the subcellular localization of nitric oxide synthase (NOS) 1 and NOS3 activity and expression within the cytosolic, plasma membrane and intracellular membrane subcellular fractions of the renal inner medulla of rats; and (ii) to determine whether NOS1 and NOS3 activity and expression in subcellular fractions of the renal inner medulla are regulated by dietary salt intake. Although the NOS system is important in maintaining Na+and water homeostasis, the identity of the NOS isoform that is sensitive to dietary Na+remains unclear. In addition, subcellular localization of both NOS1 and NOS3 has been shown to regulate enzymatic activity and influence the ability of NOS to produce nitric oxide (NO).Renal inner medullae were dissected from male Sprague‐Dawley rats and separated into cytosolic, plasma membrane and intracellular membrane fractions for measurement of NOS activity and western blot analysis.On a normal‐salt diet, NOS activity and NOS1 and NOS3 protein expression were present in all three subcellular fractions, although total NOS activity was enriched in the intracellular membrane fraction. In response to a high‐salt diet, urinary nitrate/nitrite (NOx) increased. Despite an increase in NOxexcretion, total NOS activity in the renal inner medullary homogenate was decreased. There were no detectable differences in NOS activity in the subcellular fractions. Expression of NOS1 protein was decreased in the cytoplasmic and plasma membrane fractions, although maintained in the intracellular membrane fraction, in response to high salt. Expression of NOS3 protein was unaffected by high salt.In conclusion, we hypothesize that NOS1 localization in the intracellular membrane is important in increasing NO production to aid Na+and water homeostasis.
RAPID EFFECT OF PROGESTERONE ON TRANSEPITHELIAL RESISTANCE OF HUMAN FETAL MEMBRANES: EVIDENCE FOR NON‐GENOMIC ACTION
Authors: Verikouki CH , Hatzoglou CH , Gourgoulianis KI , Molyvdas PA , Kallitsaris A , Messinis IE 
Published: September 2007

SUMMARY

The factors that regulate human fetal membrane transport mechanisms are unknown. The aim of the present study was to investigate the effect of progesterone on transepithelial electrical resistance (RTE) in the human amniochorion.
Fetal membranes from uncomplicated term pregnancies were obtained immediately after vaginal or Caesarean deliveries. Intact pieces were mounted as planar sheets separating an Ussing chamber. Progesterone (10−4 to 10−7 mol/L), mifepristone (10−4 to 10−8 mol/L) and combinations of progesterone plus mifepristone were applied to the chambers facing the fetal or maternal sides of the membrane. The RTE was measured before and 1, 5, 10, 15, 20, 25, 30, 45 and 60 min after each solution was added (at 37°C). The RTE was calculated in Ω.cm2, according to Ohm's law.
The mean (±SEM) basal value of RTE before the application of any substance in all experiments was 29.1 ± 0.4 Ω.cm2.  The net change in the RTE (ΔRTE) in relation to the basal value was calculated in each experiment. Progesterone, mifepristone and the combination of progesterone and mifepristone induced a rapid, surge‐type increase in RTE during the 1st min on both sides of the membrane. The combination of progesterone plus mifepristone exerted a synergistic action. The effect was stronger on the fetal side than on the maternal side for all substances tested (P < 0.05). The highest ΔRTE during the 1st min on the fetal side was seen with the combination of progesterone plus mifepristone (4.0 ± 0.3 Ω.cm2) and the lowest ΔRTE occurred with mifepristone (1.5 ± 0.1 Ω.cm2).
The present results demonstrated that the RTE of human fetal membranes increases rapidly in response to progesterone. It is possible that changes in RTE play a role in the control of membrane permeability during pregnancy.
FUNCTIONAL INTERACTION BETWEEN DPI 201‐106, A DRUG THAT MIMICS CONGENITAL LONG QT SYNDROME, AND SEVOFLURANE ON THE GUINEA‐PIG CARDIAC ACTION POTENTIAL
Authors: Kang Jiesheng , Chen Xiao‐Liang , Reynolds William P , Rampe David 
Published: September 2007

SUMMARY

Sevoflurane produces QT prolongation on the electrocardiogram, predominantly via inhibition of the slow delayed rectifier K+ current. DPI 201‐106 is an experimental drug that produces QT prolongation by reducing Na+ channel inactivation, thereby mimicking congenital long QT syndrome type 3 (LQT3). The present study explores the electrophysiological consequences of administration of sevoflurane in the presence of impaired Na+ channel activity.
We examined the effects of sevoflurane and DPI 201‐106, alone and in combination, on the cardiac action potential of guinea‐pig ventricular myocytes using standard microelectrode techniques.
Both sevoflurane and DPI‐201‐106 prolonged action potential duration, with the combination of the two drugs producing greater than additive effects. Similarly, instability and triangulation of the action potential waveform, measures of pro‐arrhythmia, were more pronounced when both drugs were combined.
Sevoflurane treatment significantly alters cardiac action potential waveforms when administered in the presence of impaired Na+ channel inactivation. These results indicate the potential for ventricular arrhythmia when sevoflurane is administered to LQT3 patients and suggests caution when using sevoflurane in this population.
Unbiased cell quantification reveals a continued increase in the number of neocortical neurones during early post‐natal development in mice
Authors: Lyck Lise , Krøigård Thomas , Finsen Bente 
Published: September 2007

AbstractThe post‐natal growth spurt of the mammalian neocortex has been attributed to maturation of dendritic arborizations, growth and myelination of axons, and addition of glia. It is unclear whether this growth may also involve recruitment of additional neurones. Using stereological methods, we analysed the number of neurones and glia in the neocortex during post‐natal development in two separate strains of mice. Cell counting by the optical fractionator revealed that the number of neurones increased 80–100% from the time of birth to post‐natal day (P)16, followed by a reduction by approximately 25% in the young adult mouse at P50–55. Unexpectedly, at the time of birth less than half of the neurones and at P8 only 65% of the neurones expressed neuronal nuclear antigen (NeuN), a marker of mature post‐migratory neurones. In accordance with these observations, NeuN acquisition by neurones in layer VIa was delayed until P16. The number of glia reached its maximum at P16, whereas the number of oligodendroglia, identified using a transgenic marker, increased until P55, the latest time of observation. Neurones continued to accumulate in the developing neocortex during the first 2 weeks of post‐natal development, underscoring fundamental differences in brain development in the mouse compared with human and non‐human primates. Further, delayed acquisition of NeuN by neurones in the deepest neocortical layers and continued addition of oligodendroglia to the neocortex suggested that neocortical maturation should be regarded as an ongoing process continuing into the young adult mouse.